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Title (dcterms:title)
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Removing Arsenic and Lead from Soils Using a Bioremediation Approach: Design, Implementation and Analysis of a Feasibility Study on Vashon Island, Washington
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Date (dcterms:date)
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2012
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Creator (dcterms:creator)
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Clay, Shannon E
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Environmental Studies
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extracted text (extracttext:extracted_text)
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REMOVING ARSENIC AND LEAD FROM SOILS
USING A BIOREMEDIATION APPROACH:
DESIGN, IMPLEMENTATION AND ANALYSIS OF A
FEASIBILITY STUDY ON VASHON ISLAND, WASHINGTON
By
Shannon E. Clay
A Thesis
Submitted in partial fulfillment
of the requirements for the degree
Master of Environmental Studies
The Evergreen State College
March 2012
© 2012 by Shannon E. Clay. All rights reserved.
This Thesis for the Master of Environmental Study Degree
by
Shannon E. Clay
has been approved for
The Evergreen State College
By
________________________
Gerardo Chin-Leo Ph. D.
Member of the Faculty
________________________
Ralph Murphy Ph. D.
Member of the Faculty
________________________
Deston Denniston, M.S.A., C.P.I.
________________________
Date
Removing Arsenic and Lead from Soils Using a Bioremediation Approach:
Design, Implementation and Analysis of a Feasibility Study
on Vashon Island, Washington
Shannon E. Clay
ABSTRACT
This thesis explores the use of bioremediation techniques at a site contaminated
with the heavy metals arsenic (As) and lead (Pb) on Vashon Island, WA in the South
Puget Sound. Soils around the South Puget Sound are contaminated with toxic quantities
of As and Pb left by an American Smelting and Refining Company (ASARCO) smelting
plant that operated for 100 years in Ruston/Tacoma, WA. This thesis reviews the history
of soil contamination by ASARCO and the relevant literature on bioremediation methods.
A feasibility study was then conducted to remove As and Pb using bioremediation
methods. This study used organic Brassica juncea plants (mustards) that accumulate soil
As and Pb into their tissues. To promote plant growth and metal accumulation, a
commercially available blend of microorganisms called SCD BioKleanTM, and biochar
(organic charcoal) were added. The performance of this 3-component guild was
compared to different combinations of these same components (mustards alone,
BioKleanTM + mustard, and biochar + mustards) to determine the optimal treatment.
Experiments were conducted in 16, 1m square plots with 4 plots devoted to each of the 4
treatments, plus 2 control plots. The hypothesis tested was that the most effective
treatment would be the 3-component guild. The As and Pb concentration in the soils were
analyzed for total metals by Freidman and Bruya Inc., a professional laboratory, before
and after the treatments were applied. To obtain funding two proposals were written and
both received funding. The feasibility study was conducted over one growing season
from the end of May through September 2011 on Vashon Island. There was a high rate of
mustard mortality 3 weeks after sprouting in all of the plots without biochar. The biochar
may have contributed to the survival of mustards by retaining moisture and by providing
nutrients for growth not found in the un-amended soil. The soil metal concentrations
showed great variability before (As = 81.33 ± 37.7 s.d. Pb=145.56 ± 111.20 s.d.) and
after treatments (As = 71.13 ± 27.33 s.d. Pb= 104.06 ± 55.98 s.d.) indicating large
heterogeneity in the soil composition. While decreases in metal concentration over time
occurred in most plots, statistical tests (t-test and Wilcoxon sign rank sum) showed that
only the 3-element guild and biochar + mustard treatments significantly reduced Pb.
There were unexpected increases in metal concentration in some plots. This suggests
transportation processes that moved the soils/metals during the study into and out of the
plots. Most plots showed a significant difference between before and after applications,
even in the control plots. This could be a result of tilling that was applied to all plots. On
the basis of this preliminary data, suggestions for future research are provided plus
improved experiments with fewer variables and increased sample size are presented. This
study and the general bioremediation approach are discussed in the broader context of
finding practical, cost-effective solutions to detoxify soil in South Puget Sound.
Appendices include grants written to fund this study.
Key words: phytoremediation, bioremediation, arsenic, lead, Brassica juncea, biochar,
microorganisms
TABLE OF CONTENTS
CHAPTER I Introduction ……………………………………………………………..1
Summary of Thesis Work………………………………………………………1
Significance and Broader Impacts …………………………………………….1
SEEDS
and Mission of the Social Ecology Education & Demonstration School
(SEEDS) …………………………………………………………………………2
Successful Grant Writing and Reporting …………………………………......4
Background……………………………………………………………………….....4
History of ASARCO………………………………………………………….....4
History of ASARCO Pollution and Cleanup……………………………..........7
Toxicology of heavy metals…………………………………………………….11
Remediation of Heavy Metals in Soils………………………………………...12
Phytoremediation……………………………………………………………….14
Advantages and disadvantages of phytoremediation………………………...16
Heavy Metal Soil Characteristics……………………………………………...17
Arsenic…………………………………………………………………………..17
Lead……………………………………………………………………………..18
Chelation………………………………………………………………………..19
Note on Genetically Engineered Phytoremediation Research………………21
Biochar…………………………………………………………………….........22
Microbes and Bioremediation………………………………………………....25
CHAPTER II Bioremediation Specific to Vashon Island…………………………...28
The Home Remedy Study Site……………………………………….……….........28
Phytoremediation with Brassica juncea…………………………………. …..29
Application of Biochar at the Home Remedy Site…………………………...31
Application of Microorganisms at the Site: BioKleanTM……………………33
Research Questions and Hypothesis………………………………………………37
CHAPTER III Materials and Methods……...……………………………………….39
Overview……………………………………………………………………………39
Materials……………………………………………………………………………39
Experimental Design………………………………………………………………39
Experimental treatments………………………………………………………41
CHAPTER IV Results and Discussion……………………………………………….44
Observations of mustard plants over growing season…………………………..44
Soil Sample Analysis Results……………………………………………………...45
Variability of Pb and As………………………………………………………45
Differences Before-After Treatment………………………………………….46
Control Plots Over Time………………………………………………………46
Summary of Results………………………………………………………………..48
Discussion……………………………………………………………………….......48
Mustard Survival……………………………………………………………....48
Discussion of Bioremediation Treatment Results……………………………49
Conclusion………………………………………………………………………….52
CHAPTER V: Suggestions for Future Research……………………………………53
How this Experiment Could Be Improved…………………………………...54
Additional Experiments…………………………………………………………...55
Biochar and Mustards…………………………………………………………55
Testing the Effects of Tilling…………………………………………………..57
Discussion of alternative Species………………………………………………….57
Note on Pteris vittata……………………………………………………………57
Grass……………………………………………………………………………59
Mycoremediation………………………………………………………………59
Afterward: Knowledge and Application……………………………………………..61
LITERATURE CITED……………………………………………………………….64
APPENDICES………………………………………………………………………….I
Additional Information…………………………………………………………………..I
USDA National Germplasm System…………………………………………………...I
Grant Proposals………………………………………………………………………….II
vii
LIST OF FIGURES
Figure 1: Tacoma Smelter...................................................................................................1
Figure 2: Tacoma Smelter Plume Footprint........................................................................6
Figure 3: Soil Distribution of Heavy Metal Contamination................................................8
Figure 4: Map of Vashon Island Site Location..................................................................28
Figure 5: Distribution of Amendments..............................................................................42
Figure 6: Change in Heavy Metal Levels in Previously Forested Control Plot over 4
Months...............................................................................................................................47
Figure 7: Change in Heavy Metal Levels in Grassy Garden Control Plot over 4
Months...............................................................................................................................47
LIST OF TABLES
Table 1: Concentrations of heavy metals allowed by Federal and State Standards……...7
Table 2: Number of Parcels on Vashon and Maury Island within 3 ranges of As
contamination……………………………………………………………………………10
Table 3. Advantages of Phytoremediation………………………………………………16
Table 4. Number of surviving mustards per plot (only plots with biochar)……………..44
Table 5. Soil Samples of Arsenic and Lead Concentrations in ppm…………………….45
Table 6. Time Series Control Plot Results………………………………………………46
viii
ACKNOWLEDGEMENTS
First, I would like to thank Matt and Lindsey for giving me the idea to attend the
Evergreen State College MES program and for supporting me through my time here. I
would like to thank The Evergreen State College for beckoning me to the Pacific North
West and Puget Sound areas and the MES program Professors. First there is Gerardo
Chin-Leo who aided me through this thesis construction and completion from making
sure my ideas were narrow enough to complete as well as checking in on the nitty gritty
details that make science fascinating. Martha Henderson allowed me to do several
learning contracts under her supervision with SEEDS. Without SEEDS support it is likely
this project would have happened. Thanks also to Ralph Murphy for being my second
MES reader. Thank you to Peter Robinson and Jenna Nelson as well as the Lab Stores
staff that aided me in my gained understanding of how to prepare samples and use the
ICP-MS. I want to now thank SEEDS, but before that I need to express thanks to
Christine and Tim for connecting me with Aaron who introduced me to SEEDS. They too
have been a support for me on the West Coast. Thank you Aaron Wood for being excited
about remediation on Vashon and getting me involved with SEEDS. Thanks to all the
SEEDS board members especially Bob Spivey. Thank you for providing the opportunity
to do this research and choosing me to write the grant for funding this project. Thank you
to the Harris & Frances Block Foundation for funding this project and thank you to the
board of the Activities Fund Grant who showed interest and support in the research!
Thank you very much to Bob and Beverly Spivey for providing your home and wisdom
through this process. Beverly, I enjoyed the artistic side of this work and might not have
survived without it! I don‘t think I could ever thank you both enough. Howard Sprouse of
the Remediators provided onsite professional advice checking to see if we had done our
research and providing important knowledge on the difficulties of conducting in situ
remediation. Thanks to Freidman and Bruye for processing the samples with special
thanks to Kurt Johnson and Brad Benson for the great communication and sample
support!!! Thank you Amy Wolf and Steve for allowing this research to be done on your
property as well as watching over the mustards while they grew (or didn‘t grow).
Finally, I would like to thank all those who helped on the ground at the site. Andrew
Long and Kyle Britz who kept the project going when I was away and who helped
construct and monitor the site while doing weekly applications. Thank you to you both
for continued interest and the want to continue this project forward. Thank you to Deston
Denniston my 3rd reader and permaculture scientist who added in some approach decision
making and classification of site soils. Also, thank you to Walker Hammond for your
continued assistance on the site, your great ability to work fast and thorough, and thank
you for help in editing and advice sharing, not to mention the production of all of the
biochar! Which brings me to thank Britton Shepherd for providing the use of his yard and
kiln for biochar production. Thank you Michael Hobbs for providing the Britton
connection. Oh yes, and thank you Austen Walsworth for continued computer support!
Thank you to my parents Jim and Nancy Clay for pushing me to attend graduate school.
It has been a grand time and I greatly appreciate all of your participation!
ix
CHAPTER I Introduction
Figure 1.Tacoma Smelter Photo Courtesy of the Department of Ecology Website
Summary of Thesis Work
The work in this thesis contributes to the efforts of the non-profit organization,
Social Ecology Education & Demonstration School (SEEDS), to aid in the removal of
heavy metals from soils on Vashon Island. The goal is to develop an inexpensive and
replicable way to reclaim contaminated sites and to make areas safe for living and for
growing food. This project is part of a larger ongoing soil remediation project called the
Home Remedy Project focusing on soil remediation in people‘s backyards and creating
community awareness of contamination issues. This thesis reports the current state of
ongoing research with the Bioremediation Home Remedy Project for SEEDS by
providing the initial data and results of the first 4 months of research. The thesis consists
of a literature review, design and implementation of a feasibility study, and the results
and discussion of that study. The later part of this document called Grounding the
Research, is devoted to other ways I have been involved with the research process such
as funding the research, providing ongoing research needs and ideas, and other projects
involved with creating awareness around this particular heavy metal contamination issue.
Significance and Broader Impacts
A consequence of industrialization is the increased presence of heavy metals in
soils. These have significant and negative consequences to human health, especially for
developing children. In the United States the Environmental Protection Agency (EPA)
1
was formed to create stricter standards and regulations on air, water, and soil pollution.
The goal of the EPA when it formed in 1970 was to repair the damage already done to the
environment and work to prevent further damage to the environment. This agency and
others have been working together to combat lingering pollution, but there is still a great
deal of work to be done. Heavy metal pollution occurring around older smelters can be
experienced far after the operation has been terminated because these metals are in their
most elemental form preventing any further breakdown into a non-toxic state. ―Heavy
metals cannot be destroyed biologically (no ―degradation‖, change in the nuclear
structure of the element, occurs) but are only transformed from one oxidation state or
organic complex to another (Garbisu and Alkorta, 2001).‖
The lingering heavy metals are one of the worst environmental problems of today.
―In the USA alone, more than 50,000 metal-contaminated sites await remediation, many
of them Superfund sites (Ensley, 2000 as found in Bennett et al., p. 432 2003).‖ In 2000,
―[s]ixty-four percent of Superfund and Resource Conservation and Recovery Act sites
[were] contaminated with both organic and heavy metal species and another 15% [were]
contaminated solely by metals (Henry, p.3 2000).‖ The magnitude of the pollution
problem near these sites illustrates the broad application area where bioremediation could
be applied.
The Commencement Bay/Nearshore Tideflats Superfund Site was established in
Tacoma and Ruston, Washington representing a highly industrialized area with 6
different hazardous waste cleanup sites within its borders including the Asarco SmelterRuston Site (EPA Region 10). Despite the work performed to date to clean up this site,
current cleanup methods available for communities with contamination are inadequate.
Many soils in the surrounding area have not been cleaned up or remediated. When soils
are ―cleaned up‖ they are simply transported to landfills and replaced with foreign soils.
The work from this research will further current knowledge of ecologically and
socially responsible processes for dealing with heavy metal contamination. A focus of
recent research, bioremediation is aimed at using biological processes to remediate
pollutions in soil and water. It can be more cost effective than current cleanup methods
and actually aims to remediate the soils rather than transport them to landfills where they
continue to remain toxic. Bioremediation uses living organisms to naturally re-assimilate,
2
accumulate, or neutralize toxins of all kinds and is argued to be an effective way to
actually restore healthy soil properties. If this bioremediation feasibility study provides
successful results, it can be applied in many of these contaminated areas.
SEEDS
History and Mission of the Social Ecology Education & Demonstration School
(SEEDS)
Headquartered on Vashon Island in Washington State, the Social Ecology
Education and Demonstration School (SEEDS) helps meet the urgent need for an
educational ecological project aimed at both local and global communities. The mission
of SEEDS is to develop and offer educational experiences that enhance people‘s abilities
to knowledgeably and creatively address the interwoven social and ecological stresses of
our time. Through an intensive and interdisciplinary study, participants are assisted in
gaining a rounded and critical understanding of current approaches to social and
ecological reconstruction. Participants are provided opportunities to test various
reconstructive strategies by means of individually designed practicum learning
experiences.
Beginning in 2009, SEEDS has played a key role in the development of what has
come to be known as the Vision for Vashon. A comprehensive community development
effort, Vision for Vashon sparked citizen work groups in affordable housing, community
health, community solar energy, alternative currency systems, food security, and
grassroots sustainability projects. The food security/food sovereignty group has become
a particularly active and robust group. SEEDS‘ goals in relation to food sovereignty
include the promotion of collaborative farming/gardening, and education in permaculture
approaches. This includes education and research on the heavy metal contamination.
This thesis was done for SEEDS who inspired, aided, and funded the researchbased educational project to discern and implement a system for removing these
contaminants using bioremediation methods. With SEEDS, our stated priority is that the
system be affordable, effective and replicable to other communities. ―We will freely
share our findings with other areas facing the challenge of contaminated soils, and we
3
anticipate that our research will benefit countless communities in their quest of restoring
land for food production and other community needs. (Harris and Frances Block Grant)‖
Successful Grant Writing and Reporting
In the Appendix you will find the grant proposal and reports written for Harris
and Frances Block Foundation who provided funding for this research and community
work with SEEDS. There is also a grant written to the Evergreen Foundation Activities
Fund who awarded $2,000 towards sample testing to be conducted at Evergreen by
students who were knowledgeable in using an ICP-MS (Inductively Coupled Plasma
Mass Spectrometer but wanted to gain more experience on the device for a real world
problem.
Background
History of ASARCO
The American Smelting and Refining Company (ASARCO) founded in 1899, is a
mining, smelting and refining company that is responsible for 20 superfund sites in the
United States. The Commencement Bay/Nearshore Tideflats Superfund Site includes the
ASARCO Smelter site in Ruston, Washington (EPA). This smelter, as seen in Figure 1,
started operating in 1888 as the Ryan Smelter lead (Pb) refinery (historylink.org). In
1890, it was bought and renamed the Tacoma Smelting and refining Company under
William Rust who sold the plant in 1905 for $5.5 million to the American Smelter and
Refining Company converting it to a copper smelter in 1912 (historylink.org). ASARCO
was founded by Henry H Rogers, William Rockefeller, Adolph Lewisohn, Anton Eilers
and Leonard Lewisohn, all big players in the United States western industrialization.
ASARCO operated the plant until 1985 when it was closed.
Smelting is the process of separating a particular metal, copper in this case, from
impurities contained in mined ore concentrates. Heating the ore concentrate to a high
temperature causes the metals to melt. Then the melted metal is smelted to produce a
specific metal, copper in this case, or a high-grade metallic mixture along with a solid
waste product called slag (Smelting, 2010). ―The principal sources of pollution caused by
smelting are contaminant-laden air emissions and process wastes such as wastewater and
slag (Weiss, 1985)‖. These contaminants remain long after smelting has been completed.
4
―Tacoma was the home of the only copper smelter in the nation to use ore with
high arsenic content, and accounted for 25 percent of inorganic arsenic emissions
nationwide (Tacoma Environment 2010).‖ Over the 100-year period of operation, some
of the byproducts such as Pb and arsenic (As) were released into the air through the
smokestack of the ASARCO smelter landing downwind of the site. Annually, around
10,000 tons of As was produced at the ASARCO smelter (Sloan, p14, 2011). These
emissions were distributed over 10,000 square miles through a very tall smokestack.
The smelter held the record for the tallest building on the west coast for many years:
The smelter was known for its tall 562 foot smokestack, which sent pollutants
up and away from the smelter into surrounding communities. While the
smelter was permanently closed in 1986 and the stack demolished in 1993, the
environmental damage was already complete. We now know that lead and
arsenic pollution was carried by the wind over a wide expanse of King, Pierce,
Thurston, and Kitsap counties. (Kingcounty.gov)
Twenty-five years after the smelter was closed, the landscape is still quilted with
contamination from the past windfall patterns. (Map below). This map shows As
contamination areas. The green outline represents the Tacoma Smelter Plume
(TSP) Study area, yellow areas have 20.1-40.0 ppm As, tan has 40.1-100.0 ppm
As, orange has 100.0-200.0 ppm As, and red has 200.0 ppm and up. The As
concentrations measured in the soils for this map were taken from the top 0-6
inches of the surface soils.
5
Map Created: December 2006 by Toxic Cleanup Program and shows the
different As concentrations (ppm) in the footprint area (Pb has similar fallout)
The EPA designated the ASARCO site as well as the 23 acre slag peninsula created
by the plant as part of the Commencement Bay Superfund site in 1979 and stopped
copper smelting in 1985 (Commencement Bay/Nearshore Tideflats Superfund Site ROD
p2-1). Due to the costs associated with the pollution cleanup, ASARCO filed for
6
protection under Chapter 11 of the United States Bankruptcy Code on August 9, 2005
(Case Number 05-21207, Southern District of Texas, Corpus Christi Division).
The ASARCO bankruptcy was the largest environmental bankruptcy in U.S.
history (EPA Compliance). ―The EPA, along with other federal and state agencies
pursued and received $1.79 billion to fund environmental cleanup and restoration under a
bankruptcy reorganization of…ASARCO (EPA Compliance).‖ The money paid went to
fund future cleanup work with the EPA and to pay for natural resource restoration
through the Department of Interior and the Department of Agriculture.
History of ASARCO Pollution and Cleanup
The funded cleanup work has enabled the EPA and the Washington State
Department of Ecology (WSDOE) to document the contamination of Pb and As in the
adjacent areas. WSDOE found concentrations of 360 parts per million (ppm) of As and
1300 ppm of Pb on certain soils on the south side of Vashon Island. This level of
contamination is well over the EPA‘s safe limit for bare soils where actions, such as
excavation, must be performed to remediate the problem. Contamination is more than
three times the EPA limit for areas with children. It is far above Washington State's limit
of 20 ppm concentration standard for As and the state's 250 ppm for Pb (WSDOE).
Table 1. Concentrations of heavy metals allowed by
Federal and State Standards.
Washington
Washington
EPA As
EPA Pb
State As
State Pb
Excavate if
Excavate if
above
above
20ppm
250ppm
230ppm
530ppm
The natural background levels of As in soils in Washington are around 7-9 ppm (San
Juan, p14). The allowable limit for As contamination is 20 ppm in residential areas (San
Juan, 1994). Background levels of Pb in Washington range from 11-24 ppm (San Juan,
p14, 1994) while allowable limits are 250ppm.
The Washington State Department of Ecology performed an initial soil test study
that looked at the depth profile and reach of the contamination in King, Kitsap, Pierce
and Thurston Counties. Glass et al. conducted and reported the first round of sampling
7
concluding soil As and Pb contamination from deposition of airborne particulates creates
depth profile in soils is where the contamination remains near the surface and
concentrations typically decrease rapidly with increasing depth, especially below 12
inches deep (p52 ). When contaminated soils are disrupted the contamination patterns
become more complex.
…depth profiles at developed properties can be more complex than in forest
areas... The occurrence of higher concentrations below 6 inches is interpreted
as more probably the result of physical soil disturbances as part of property
development than a result of mobilization/leaching of arsenic and lead absent
physical disturbance. (Glass et al., 2000)
Most contamination is found within the top 2 inches (5.08cm). However, there are some
occurrences of the maximum As and Pb concentrations in individual samples being at a
depth below 6 inches and is likely the result of parcel development actions and soil
disturbance that altered the typical depth profiles for undisturbed locations, on a propertyspecific basis (Glass et al., 2000). There are several factors that will determine a
property‘s concentration of contamination from the smelter. The King County website
sums this up well in the following excerpt.
The amount of Asarco arsenic and lead is in the soil in any area of King County depends
on several factors, including distance from the smelter, topography, and history of the
property in question. Here are some rules of thumb to figure out the chances that your
property has contamination:
Distance: The most contaminated soils tend to be in coastal King
County from Seattle to Federal Way and on Vashon-Maury Island.
Topography: Soil on hillsides that face southwest tended to get
more of the contamination than east and north facing hillsides
because of the way the wind traveled and carried the
contamination.
History of the property: Arsenic and lead tends to stay in the top
six inches of soil. If the soil on a property was dug up, moved, or
otherwise "disturbed" over the last 100 years, there may be less
contamination there than on a property that was undisturbed for
the entire time the smelter operated (from the late 1800s to 1986).
http://www.kingcounty.gov/healthservices/health/ehs/toxic/TacomaSmelterPlume/resid
ents.aspx
Figure 3: Soil Distribution of Heavy Metal Contamination
8
Now that a clearer picture has been generated of the contamination distribution and what
guidelines are in place for cleanup, concentrated efforts for cleanup has occurred
targeting specific levels of contamination.
At the smelter location, cleanup consisted of building an onsite containment
facility, removing the soil from the site and neighboring yards, placing the contaminated
soil into that containment facility, and then terracing and capping the entire smelter site
with the contaminated soil inside. The site is now monitored for leaching and other signs
of contamination leaving the containment area. Information on this process can be found
at http://yosemite.epa.gov/R10/cleanup.nsf/sites/asarco. All zones were children
congregate, such as schools and playgrounds, with elevated contamination levels have
been excavated in Tacoma, King County and on Vashon/Maury Island, but personal
property has not been attended to. Many residents on the island are not even aware that
there is a contamination issue. Talking to new residents on the island it is noticed that
they often are not aware of the heavy metal issues. Part of the cleanup process is making
sure people become informed about the heavy metal contamination on the Island.
A second settlement was reached in 2010 between ASARCO and the state of
Washington. $188 million has been paid to cover the costs of the state for past ASARCO
related cleanup and for funding further cleanup of highly contaminated areas. $3.9
million is going to The Washington Department of Ecology to be used for further
sampling and cleanup (EPA Cleanup). Currently, one of the main programs funded from
the settlement with the Department of Ecology is the Dirt Alert Soil Safety Program. The
program is going to provide free testing of soils for public parks, camps, and publicmulti-family housing play areas in contaminated areas as well as outreach and education
on how to protect children from being exposed.
Although the Commencement Bay Superfund site does not include the
surrounding areas with extreme heavy metal contamination, yard sampling is available on
request. If the soils are found to be contaminated at levels afforded by the bankruptcy
funds then cleanup will occur. Now, in 2011, the EPA and Department of Ecology is
focusing on properties with contamination with an average above 100ppm As or any
sample above 200ppm As including any sample containing above 500ppm Pb (Amy
Hargrove, Personal Communications). This process consists of digging the soil up,
9
removing it and trucking it to landfills, then replacing it with foreign soils. The soils are
not remediated. Although this service has been available for contaminated sites in Ruston
and Tacoma, it has not been readily available on Vashon and Maury Island.
Soil remediation is a necessity for the Vashon community in order to enable
reliable, healthy and local food sourcing; an imperative for an island community that does
not have easy access to produce from the mainland. Vashon residents are dealing with
widespread heavy metal soil contamination from the ASARCO smelting plant. The
southern half of the island was under the smelter plume windfall area, leaving it
contaminated with mass amounts of the heavy metals As and Pb.
Table 2: Number of Parcels on Vashon and Maury Island within 3 ranges of As
contamination. Created using Tacoma Smelter Plume Footprint Map in GIS in
correlation with parcels in each contamination zone. Arsenic level is shown in parts per
million(ppm).
By Shannon Clay November 2010
2,369 parcels show contamination with samples showing 100-200ppm of As. Even more
concerning are the 3,416 parcels with contamination from 200ppm up to 1,050ppm. Little
has been done to remediate for this contamination in this highly populated areas.
10
Even though ASARCO filed for bankruptcy at several of it‘s locations in 2005,
they were bought by an international Mexico/Thai corporation conglomerate called
GrupoMexico. The company operates three open pit copper mines and associated mills
and copper smelter in Arizona as well as a refinery complex in Amarillo, Texas
(GrupoMexico, 2011). They produce copper cathode, rod and cake precious metals and
by-products (ASARCO.com/products)‖.
Toxicology of heavy metals
Heavy metals are defined as elements with metallic properties and an atomic
number >20 (Jing et al., 2007. They occur naturally in the environment, but most heavy
metals become toxic to humans, other animals and microorganisms at certain levels of
contamination. Pb, however, can be a poison when ingested even in small amounts. The
current standard from the Centers for Disease Control and Prevention (CDC) defines
childhood Pb poisoning as a whole-blood Pb concentration equal to or greater than 10
micrograms/dL (Medical Dictionary). However, current research shows that smaller
doses can affect children negatively. This is because Pb replaces other minerals that the
body needs while blocking protein receptors changing the shape of the protein making it
so the protein cannot connect to the metals it was originally meant to connect with. At
that point, the protein cannot perform the necessary function. Depending on the person,
even small amounts of Pb can cause complications. Pb accumulates in the body causing
development problems in children, infertility in men, it displaces calcium in bones and in
the brain diminishing brain function, and can cause low or high blood pressure (ATSDR).
Possible complications in children include behavior or attention problems,
failure at school, hearing problems, kidney damage, reduced IQ, and slowed
body growth. Other symptoms of lead poisoning may include abdominal pain
and cramping (usually the first sign of a high, toxic dose of lead poison),
aggressive behavior, anemia, constipation, difficulty sleeping, headaches,
irritability, loss of previous developmental skills (in young children), low
appetite and energy, and reduced sensations. Very high levels of lead may
cause vomiting, staggering walk, muscle weakness, seizures, or coma.
(Medline Plus, accessed 2011)
Arsenic, the most common toxic metal widely occurring in the environment
(Bhakta et al., 2010), poses serious hazardous impacts not only to human health and also
11
has ecosystem wide consequences. It has been identified as a common cause of acute
heavy metal poisoning through ingestion or inhalation posing severe health risks
(Murphy et al. 1989) (Smith et al. 2009) As poisoning is caused by increased levels of As
in the body and leads to apoptosis or programmed cell death (Balakumar, 2009).
King County is an area in Washington highly contaminated from the ASARCO
smelter plume and has relayed the following information to the public over the internet:
Acute (short-term) arsenic poisoning may cause nausea, vomiting, diarrhea,
weakness, loss of appetite, shaking, cough and headache. Chronic (long-term)
exposure may lead to a variety of symptoms including skin pigmentation,
numbness, cardiovascular disease, diabetes, and vascular disease. Arsenic is
also known to cause a variety of cancers including skin cancer (nonmelanoma type), kidney, bladder, lung, prostate and liver cancer. (King
County Health Services, 2011)
In depth information on the toxicology and health effects can be found on Agency for
Toxic Substances and Disease Registry (ATSDR‘s) website where hundreds of research
articles are documented. Most incidents of heavy metal exposure from soils occurs by
ingestion of the soil, in the home from soil being carried in on garments through
inhalation and through the mouth. Children, who often play in and around dirt, are often
at increased risk. This shows how farming and gardening increases risk for those
involved in such activities and why actions need to be made to improve these working
environments.
Remediation of Heavy Metals in Soils
The most common decontamination method for polluted soils is to dig out and
remove the soil and deposit it in landfills. This is a way to remove the soils from
immediate concern, but does not actually remediate the issue. This process merely
confines the contaminated soils with out decontamination. More rigorous remediation
techniques can both remove and recover heavy metals through soil washing, scrubbing
with wet screening, and through chemical methods using organic and inorganic acids,
bases and salts and chelating agents. ―[C]hemicals used to extract radionuclides and
toxic metals include hydrochloric, nitric, phosphoric and citric acids, sodium carbonate
and sodium hydroxide and the chelating agents EDTA (Salido et al. 2003) and DTPA.‖
12
(Adriano et al.) All of these methods generate secondary waste products that require
additional hazardous waste treatments. Plus, in order to use these methods the soil must
be transported to a treatment facility or they are tested in greenhouses and laboratories,
but not enacted on site where the problem is occurring causing an increase in cost for
transportation an possible spread of the toxic soils.
In situ means applying methods on site. This is beneficial for a number of reasons.
In situ research lessens the chances of contamination elsewhere and helps in
reestablishing healthy ecosystems within the contaminated soils providing a true
remediation. Most on site treatments are done using bioremediation methods. An area of
increased research, bioremediation and phytoremediation of heavy metals in soil, focus
on more efficiently removing and re-accumulating the heavy metals laden within the soils
rather than simply transporting the soils to a landfill. There is also research that looks at
immobilizing the metals to reduce the likelihood of ingestion or metals reaching
waterways (Friesl et al. 2003; Akhter et al. 1990; N.T. Basta 2000).
Originally, bioremediation defined all types of remediation using living organisms
from trees to microorganisms to remove or neutralize contaminants in water and soils. At
this time bioremediation often refers specifically the use of microorganisms to remediate
polluted soils. In this thesis, bioremediation is used as a categorical name given to all
biological remediation processes. Phytoremediation would fall within this category and is
defined as ―the use of plants and trees to remove or neutralize contaminants in polluted
water or soil (thefreedictionary.com 2011)‖. This leaves no name to describe remediation
using specifically microorganisms. In this paper it will simply be referred to as
―remediation with microorganisms‖.
Bioremediation in all of its forms has been suggested as a more efficient, cost
effective, and environmentally sound way to treat heavy metal soil contamination. Most
research on bioremediation has been done ex-situ (in a lab/controlled environment). It is
important that this research be done in-situ/in the field to make sure it is effective within
the contaminated environments. If an effective method is found, many hazardous waste
sites could be remediated around the country and the world. ―Phytoremediation has the
potential to clean an estimated 30,000 contaminated waste sites throughout the US
13
according to the EPA‘s Comprehensive Environmental Response Compensation Liability
Information System (CERCLIS) (Henry, 2000).‖
Remediation of heavy metal contamination in soils is more difficult than other
pollutants as explained previously. It is costly to dig up and haul the soils away.
Until now, methods used for [heavy metal] remediation such as excavation
and land fill, thermal treatment, acid leaching and electroreclamation are not
suitable for practical applications, because of their high cost, low efficiency,
large destruction of soil structure and fertility and high dependence on the
contaminants of concern, soil properties, site conditions, and so on. Thus, the
development of phytoremediation strategies for heavy metals contaminated
soils is necessary (Chaney et al., 2000; Cheng et al., 2002; Lasat, 2002).‖
(Jing et al. 2007)
Bioremediation is often suggested as a less expensive form of remediation compared to
other processes such as digging and hauling the soils away, or capping the contaminated
soils with cement. ―Common remediation methods include soil washing, excavation and
reburial for metal-contaminated soils, and pump and treat systems for water (Glass,
1999).‖ All of these methods require removing the soils from their residing location.
Phytoremediation
Within the past 30 years extensive research has gone into finding species that not
only thrive in toxic environments, but that can aid in the remediation of those
environments. Species range from grasses, agricultural crops, and wild plants to
microorganisms and mushrooms. Inspiration for the idea of Phytoextraction occurred
with the discovery of a variety of wild plants, often endemic in naturally mineralized
soils that contained high levels of heavy metals in their foliage. Baker (1981) suggested
this was due to the plants evolving within these toxic environments to be able to tolerate
previously toxic amounts of non-essential metals within their systems (Raskin et al.,
1997). Phytoremediation can be conducted in many ways. Phytoaccumualtion/
Phytoextraction is the removal of metals from contaminated soils whereby the metal is
extracted from the soil, and then translocated to, and concentrated in, the harvestable
parts of the plants (Mejár and Bülow 2001, Chaney et al. 2000, Cunningham et al.1995).
The harvestable parts can then be ashed to extract the metal resources. The incineration
14
of the harvested phytoextraction plants and the collection of the metals for sale is termed
phytomining by Anderson et al., 1999). Alternatively, other methods of
phytoaccumulation either discard the other harvestable parts of the plant, or they may be
ashed to reduce size and then discarded.
These metals are accumulated through the plants need for essential metals
necessary for growth. While the plant is accumulating these essential metals, they can
accumulate non-essential metals and metals without known biological functions. Many of
these species of plants are capable of accumulating non-essential heavy metals, including
As and Pb, into the plant roots, but fewer can amass the metals into the aerial/harvestable
parts for the plant. The metals are mostly accumulated through the plant roots but can
accumulate them from their aerial surfaces as well. Plants that are capable of achieving a
shoot to root metal concentration ratio greater than 1 are known has hyperaccumulators
(Salido et al., 2003; Baker, 1999). The accumulation of metals in hyperaccumulators
often reaches 1–5% of the dry weight (Raskin et al., 1997).
The amounts of metal absorbed by a plant depend on: (i) the concentrations
and speciation of the metal in the soil solution; (ii) its movement from the
bulk soils to the root surface; (iii) transport from the root surface into the root;
and (iv) its translocation from the root to the shoot. (Wild, 1988 as quoted by
Patra et al., p 203)
Many phytoaccumulators grow slowly, remain small and do not accumulate many metals
due to their size. Sea purslane is a plant that can phytoaccumulate both As and Pb, but it
has only a small amount of biomass. ―The ideal plant for phytoextraction should grow
rapidly, produce a high amount of biomass, and be able to tolerate and accumulate high
concentrations of metals in shoots (Kumar et al.1995).‖ A successful remediation will
most likely use a larger plant that will grow quickly to accumulate more metal faster
accumulating a decent amount of metal for each harvest. The greater the amount of heavy
metal that accumulates before each harvest the less time necessary to fully remediate a
site. The time needed for remediation dependens on ―the type and extent of metal
contamination, the length of the growing season, and the efficiency of metal removal by
plants, but normally ranges from 1 to 20 years‖ (Kumar et al. 1995a; Blaylock and
Huang, 2000 as cited by Narasimha, 2003).
15
Other forms of soil phytoremediation include phytostabilization where heavy
metal tolerant plants grow on site to reduce the mobility of heavy metals by securing the
soils and reducing leaching into groundwater and the polluted soils becoming airborne
(Salt et al., 1995). Most of these plants remain in place and are not harvested.
Advantages and disadvantages of phytoremediation
Bioremediation practices tend to be low cost, when compared to other methods
for remediation (Lloyd and Renshaw, 2005). However, many on the ground
bioremediations fail due to uncontrollable variables and the need for attention over a
longer period of time than removing the soils to a landfill. In the table below is a
comparison of the advantages and disadvantages of the bioremediation method
phytoremediation.
Table 3. Advantages of Phytoremediation.
Advantages
Disadvantages
1. Environmentally friendly, cost-effective, and
1. Relies on natural cycle of plants and therefore
aesthetically pleasing;
takes time and replication
2. Metals absorbed by the plants may be extracted
2. Some plants absorb a lot of poisonous metals,
from harvested plant biomass and then sustainably
making them a potential risk to the food chain
recycled;
if animals feed upon them.
3. Phytoremediation can be used to clean
3. Application varies depending on pollutant
up a large variety of contaminants;
and site being treated
4. May reduce the entry of contaminants into the
environment by preventing their leakage into the
groundwater systems.
4. Phytoremediation works best when the
contamination is within reach of the plant roots
5. Actually remediates soil rather than covering it up
5. Requires upkeep and access to ample sun and
or moving it to another location still contaminated.
water
Original Table from Hong-Bo et al. p24 2010 with additions made to include more
advantages and disadvantages.
The costs involved in phytoextraction could be more than ten times less per hectare
compared to conventional soil remediation techniques as reported by Salt et al. (1995).
Other environmental benefits of phytoextraction/phytoremediation include low impact
and the prevention of erosion during the remediation process because of plant coverage
16
of the soil. To remove sufficient amounts of heavy metals with this technique, plants have
to be highly efficient in metal uptake and translocation into their aboveground vegetative
parts so more metal can be stored within the plant. The most limiting factor however, is
the ability for the plants to be able to access the metals within the soils for accumulation.
Heavy Metal Soil Characteristics
Heavy metals within soils are distributed within the soil structure binding to various
components. These binding connections determine the metals‘ mobility and
bioavailability. The nature of this association is often defined through the ―speciation‖ of
the metal. Metals found in soil environments exist in six forms: (I) water-soluble free
metal ions that are very mobile; (II) carbonate complexes, still mobile but bound; (III)
metal ions occupying ion exchangeable sites that are specifically adsorbed onto inorganic
soil constituents, less mobile; (IV) organically bound metals; (V) compounds of oxides
and hydroxides that are relatively immobile; and (VI) metals in the structure of silicate
minerals, which are basically stuck (Tessier et al. 1979; Ahumuda et al., 1999). Only
speciated metals forms (I), (II) and some components of form (III), are readily
bioavailable (Tessier et al., 1979). This poses a problem for phytoremediation because
some metals will not budge within the environment depending on how they are connected
and speciated within the soil ecosystem.
Arsenic
Arsenic is found in group 14 on the Periodic table meaning that in its most
elemental form (not bound to anything) it has a valence of 3. ―The extent/rate of
bioaccumulation and sorption/desorption processes are highly influenced by chemical
species specific in the plant-water-soil systems. Whereas the trivalent states of As, As(III)
also called arsenite, are mobile in the reduced soil-water systems, the pentavalent, As(V),
species are relatively immobile under oxidizing conditions due to the strong fixation
mechanisms in soil matrices. Both species, however, have been hyperaccumulated by
plants. ―As(III) and As(V) as well as methylated As species have been found in plant
tissues‖ (Hooda ed., 2010). As(III) has been found to be less common than As(V) on
17
Vashon Island. Out of 25 samples taken by the Department of Ecology speciation of the
smelter plume contamination was found as follows:
As (III) concentrations ranged from a minimum of 0.086 mg/Kg… dry weight
(dw) to 1.93 mg/Kg. None of the As (III) concentrations exceed the MTCA
SSL of 7 mg/Kg dw…for the protection of wildlife Based on EPA Method
1632, As (V) concentrations were calculated:
As (V) = Total As5 – As (III)
Since only small amounts of As (III) were detected in soil samples, the As (V)
concentration was only slightly less than the total As concentration. The
minimum As (V) concentration was 7.140 mg/Kg dw and the maximum was
282 mg/Kg
dw. (Sloan, 2011)
Most information on As and Pb contamination are on the total recoverable metals found
in the soil because this analysis is less expensive and easier to do. Thus, the
contamination from the plume is not as extreme as it could be if more of the As was
trivalent (+3). Other research shows that the As does not move much within the soil
column and is not prone to leaching into waterways (Glass, 1999)
Lead
Lead is in the carbon group on the periodic table. Its most common formations
have tetravalent ( +4) or divalent (+2) bonding ability. Pb+2 is bioavailable within the
human digestive tract causing it to be the toxic form of Pb (Miretzky and FernandezCirelli, 2007). Its metallic nature causes it to be attracted to organic compounds within
soils. Pb is extremely insoluble and generally not available for plant uptake in normal
ranges of soil pH (Manceau et al., 1996). Pb has high affinity to organic matter such as
Fe-Mn oxides and clays and precipitates as carbonates, hydroxides, and phosphates
(McBride, 1994). Generally, Pb is trapped within soils as insoluble Pb phosphate (Hooda
et al. p315). In order for an element to be absorbed or accumulated it must be
bioaccessible and bioavailable. Therefore, adding phosphate to environments low in the
nutrient will actually cause Pb to bind and become insoluble. Chelators are used to make
Pb more bioaccessible, but in some cases using extreme chelators has resulted in Pb
18
becoming too soluble resulting in contamination of groundwater with the Pb (Hooda et
al.). Discussion on chelators is found under the chelator subchapter.
In this type of research it is vital to know the species of Pb and As being dealt
with and how different amendments and applications change the speciation to be more
available and mobile or not. This type of scientific analysis for speciation of metals is
rather costly. One advantage is that Vashon Island‘s contamination is from an
anthropogenic source of contamination (the smelting). Metals from anthropogenic
sources often are more mobile than naturally occurring metals (Lou et al. p5 2008;
Kashem et al., p248 2011). We also have previous studies that indicate there is more As
(III) than (V). Other research has found the most common species of Pb found in
contaminated soils form smelters is Pb+2 (Morin et al, 1999).
Research is now being done within the smelter plume area to look at
environmental impacts other than human health to assess terrestrial ecological impacts
and see what impacts the contamination has on wildlife systems. The Model Toxics
Control Act (MTCA) calls for terrestrial ecological evaluation (TEE). As cited
previously, The Washington State Department of Ecology conducted a TEE looking at
the Tacoma smelter plume area and the Hanford Old Orchards. The document can be
found on the department‘s website at www.ecy.wa.gov/biblio/1103006.html or you can
call and request the Ecological Soil Screening Levels for Arsenic and Lead in the Tacoma
Smelter Plume Footprint and Hanford Site Old Orchards document.
Chelation
Chelation is when a ligand bonds to and around a central atom with two or more
bonds forming a complex molecule. This bonding occurs with a metal ion as the central
atom making the metal ion unable to bond with anything else but the ligand. Different
chelating ligands are attractive to different metals. The ligands are formed in such a way
that makes binding to particular metals very attractive. The attraction is so that it will
debond metals from other bonds. For example, Pb commonly has 2 or 4 electrons
available for binding to other elements. When a chelator, having 2 or 4 bonding locations
available to Pb-, is added to Pb contaminated soils it makes the Pb more mobile. The Pb
is now bonded to the ligand not the soil and the ligand is only bound to the Pb ion. Thus,
19
the Pb is freed from the other various elements and organic compounds within the soil
causing the Pb to be immobile. New bonds are made with the available ligands and the
Pb becomes available.
Extensive research has been done using synthetic chelates to increase plant uptake
of Pb and some with As. (Mentioned before, As on Vashon Island is mostly the more
immobile As(V)). Ilya Raskin, a prominent scientist in the phytoremediation field, used
ethylenediaminetetraacetic acid (EDTA) to chelate Pb and As and make them more
bioavailable for uptake by B. juncea.
EDTA acts by complexing soluble metals present in the soil
solution. As the free-metal activity decreases, the dissolution of
bound metal ions begins to compensate for the shift in equilibrium.
The process continues until the supply of EDTA-extractable metal
is exhausted. (Raskin 1997)
The results showed an increase in Pb uptake by the Indian mustard. ―…the application of
accumulation in the shoots of B. juncea”(Raskin, 1997). In order for a plant to be
considered as a hyperaccumulator it must sequester at least 1%, but with the EDTA the
plants were almost sequestering up to 2% of the Pb in their roots.
Although the research provided some exciting possibilities it also presented other
problems. The chelated metals provided too much mobility allowing the heavy metal
contamination to move into the groundwater and severely pollute it. After this discovery,
regulators would no longer issue permits for field research of synthetic chelating of Pb in
the US or in Europe (Hooda et al. p.329). EDTA is a strong chelator and results in
undesired effects due to the slow degradation of the compound. Other research shows
EDTA prevents cell division, chlorophyll synthesis and algal biomass production
(Oviedo, 2003).
It is possible that using a weaker chelator would make Pb and As available
without endangering the soil health as well as the surrounding environment. Strong
chelators may bond minerals too strongly as well making the mineral unavailable to
plants while a weak chelating agent may not be able to bond the mineral enough to
prevent it from interacting with other compounds also reducing their availability to plants
as they become more entrenched within the soils to other elements.
20
There are natural chelators as well. Some grasses are known to chelate by
producing and releasing phytosiderophores to make metals more available for plant
uptake (Ma and Nomoto, 1996). Bacteria also can secrete natural biosurfactants
enhancing the bioavailability of metals (Volkering et al. 1998). These grasses could be
used at the Home Remedy Site in combination with the hyperaccumulators and might be
a focus of future research.
Note on Genetically Engineered Phytoremediation Research
Mejár and Bülow conducted extensive phytoremediation research by introducing
proteins called metalothioneins from mammals into hyperaccumulating plants. Of
particular interest were the enzymes called phytochelates (PCs). Organisms respond to
heavy metal stress using different defense systems, such as exclusion,
compartmentalization, making complexes and the synthesis of binding proteins such as
metallothioneins (MT) of which phytochelatins are grouped under (Mejár and Bülow,
2001). Plants synthesize phytochelates when their cells come into contact with toxic
heavy metals (Mejár and Bülow, 2001). The PCs allow the heavy metals to move more
freely throughout the plant so that it can be stored in an area of the plant that is less toxic
to the plant for better plant survival. Researchers found that through genetic engineering
the over expression of these enzymes increased uptake of metals into roots and shoots but
did not find an increase in overall accumulation. PCs from E. coli were also used, as E.
coli has one of the strongest PCs, in B. juncea by Zhu et al. resulting in transgenic plants
that accumulate more Cadmium than wild B. juncea plants. Genetic engineering (GE) is
an approach to manipulate plants genetically to acquire traits that are desirable functions
for humans. This type of science may lead to unwanted results with GE plants cross
pollinating with wild plants and changing natural evolutionary processes. Research has
shown that GE plants can affect animal‘s reproductive processes as in the moth that was
exposed to GE pollen and became sterile (Zangerl, 2001). GE plants could cross pollinate
with wild varieties causing these plants to also hyperaccumulate the toxic metals. Then
the plants would be toxic to any animal ingesting the plant (Snow, 2002; Global Justice
Ecology Project). Due to the uncontrollable nature of these plants, the author of this
thesis highly advises against their use.
21
Biochar
Biochar is organic matter that has been combusted in the absence of oxygen in a
process known as pyrolization creating charcoal. The term biochar is modern and, in this
paper, references charred organic matter that is deliberately applied to condition soils.
The modern ―discovery‖ of biochar comes from ancient soils called Terra Preta, or
Amazonian Dark Earths. Soils from archeological sites throughout the Amazon contain
very high levels of charred organic material. This charred carbon is thought to be a result
of agricultural practices in the area with Terra Preta dating to as early as 8000 BP
(Taylor, 16), improving the quality of the native soils of the time. Even though the people
that made them vanished long ago, the charred material has remained a beneficial soil
constituent within Terra Preta remaining the most productive soil in the Amazon to this
day.
Presently, the use of biochar is focused in three main areas of interest and
potential use:
1. The most publicized is the possibility of using biochar for carbon
sequestration.1
2. As a soil amendment (Taylor, 18).
3. Remediation of toxins from soil and water.
This paper focuses on using biochar for its ability to absorb water within the soils, to
increase cation and anion exchange capacity, and provide beneficial environments for
microorganisms and plant roots. It is important to understand how biochar is made in
order to identify its soil benefits. Biochar is made through pyrolysis, which is the process
of combusting organic matter, called feedstock, in the absence of oxygen. This retains
carbon in solid form rather than converting it into CO2. During this process most of the
volatile elements in the feedstock change to a gaseous form and escape from the carbon
________________________________________________________________________
1. Burying large amounts of biochar could potentially be a way to sink and store carbon
by preventing it from entering the atmosphere, and therefore slowing or reversing climate
change. Of course this is depends on the way it is produced. Often a forest used to make
biofuel or biochar holds more CO2 than what would end up being preserved in the soils.
22
structure. These escaping gasses leave tiny holes in the carbon structure and result in a
greatly increased surface area. This increased surface area is what gives biochar most of
its beneficial properties.
Two main factors affect the properties of a biochar; feedstock and treatment
temperature. Different feedstocks produce different biochars with different properties.
Biochar made from manure will have very different properties than biochar made from
walnut shells. The original feedstock contains various matrices of compositions of
elements, some volatile and some not. Mineral elements in a feedstock are not volatile
and are always preserved when charred. This leaves nutrients necessary for plant growth
within the biochar. Other elements will volatilize and/or oxidize to varying degrees
depending on treatment temperature. The feedstock will affect both the surface area of a
biochar and what elements remain in the biochar in addition to carbon. For example,
biochars made form wood tend to have a pH around 7.5 and Phosphorous in the level of
6.8 g/kg, Nitrogen at 10.9 g/kg and Potassium at 0.9 g/kg of biochar (Lehmann and
Joseph, p69).
Treatment temperature also has a great effect on a biochar‘s properties. Pyrolysis
begins once feedstock is heated to 350C at which point volatile elements begin to turn to
gasses. The surface area increases as the gasses erupt forth, leaving empty macro- and
micropores behind. Depending on feedstock, this continues with increased treatment
temperatures up to around 750C. When a temperature of 750°C is reached the carbon
structure will start to deteriorate and surface area will decrease (Brown et al. 2006). Both
the type of feedstock and the temperature at which it is pyrolized will result in production
of materials for different applications.
Biochar and its high surface area can have many potential benefits for both
remediation and agriculture. Lehmann and Joseph‘s extensive textbook, Biochar for
Environmental Management, includes hundreds of research documents providing a
substantial understanding of biochar. The book maintains that when feedstock is going
through pyrolysis micro-pores and macro-pores are formed at different heat ranges. The
micro-pores can retain nutrients, contaminants and water while macro-pores provide
habitat for microorganisms and roots. (Lehmann 2009, p25). Research shows that biochar
holds more water than activated carbon (Pietikäinen et al. 2000 as cited in Lehmann p87)
23
and acts like a sponge absorbing the water and the nutrients the water contains.
Depending on the biochar‘s properties, it can have a special affinity for certain types of
molecules by attracting elements with positive and negative charges to different locations
within the char. This is a form of adsorption, which is when molecules and particles bind
to a surface, in this case the biochar. The high surface area of biochar contributes to
nutrient adsorption through charge or covalent interactions (Verheijen et al., 2010).
Surface area only increases if the feedstock is pyrolized at temperatures above 500C
(Verheijen et al., 2010). This is important in remediation and will determine whether or
not certain bonds will remain in the current soil structure or change when the biochar is
added.
Additions of biochar have shown increase in the cation exchange capacity (CEC)
and anion exchange capacity (AEC) of soils. CEC is a measurement of how well a soil
can adsorp2 and exchange cations including K+ and NH4+ while AEC is the measurement
of how well anions, such as NO3- and PO42-, can be exchanged (WSU Tree Fruit
Research and Extension Center). High surface area increases CEC because the surfaces
of clays and organic matter have negative charges and can bond easily to cations. Low
CEC results in nutrients leaching away. Generally, the more surface area there is in a soil,
the better nutrients are stored especially with smaller pore sizes. Root hairs have a CEC
also and exchange an H+ for a cation nutrient. Biochar holds nutrients providing a longterm source of organic matter for plants to draw from. High CEC prevents leaching of
nutrients and metals. This allows stores of nutrients to be maintained within the soils
longer creating a healthier growing environment for plants.
With the increase in CEC and AEC within the soils, biochar can have a similar
effect as chelating ligand bonds because it can retain and release metal ions. It allows the
attractions of the metals bound within the soils to find new attractions and move
throughout the soil system. However, it is also presumed that biochar adsorps2 metals
which would decrease uptake to plants unless a strong relationship is formed between the
microorganisms living within the biochar and the plants growing there. When biochar is
________________________________________________________________________
2. Adsorp is different than adsorb. Adsorption is when a substance attracts and holds
other materials or particles to its surface (The Free Dictionary).
24
added to soils, microorganisms quickly move into the macropore spaces to live. There
they interact forming diverse living cultures that can be supported for centuries among
the diverse pore spaces. They also aid in plant uptake of nutrients by interacting with the
adsorped elements and plant roots.
Research conducted by Namgay et al. showed successful uptake by plants of Pb at
certain biochar concentrations added to the soil. When biochar was added at a rate of 15
g/kg to Pb polluted soils, Pb uptake was significantly increased compared with biochar
applied at a rate of 5 g/kg (Namgay et al., p641 2010). In other research biochar has been
used to reduce the bioavailability of heavy metals by sorbing the metals to the char while
the char released nutrients for plant growth. The only metal that had an adverse reaction
was Pb. Research done by Beesley et al. showed that the addition of biochar to multi
element contaminated soils showed an increase in soluble Pb and As while all other
elements decreased in solubility over time. What was also interesting about this research
was an increase in As above concentrations found in the initial contaminated soil samples
(Beesley et al.), p.2286). This maybe due to As becoming more bioavailable than prior to
the biochar addition.
Biochars can have widely varying properties but in general they all have a high
surface area (measured in meters squared per gram) created by small pores providing
infrastructure for a healthy soil ecology and retaining water. These are advantages for use
in both remediation and agriculture.
Microorganisms and Bioremediation
Beneficial cultures of microorganisms (microbes) are shown to improve soil
microbial ecology (Sanita di Toppi and Gabbrielli, 1999). The development and use of
microorganisms is a growing field of study with a wide range of possibilites in how to
best use this knowledge. Different blends/cultures of microbes are currently used to
increase crop yields as well as combat heavy metals. For example, As creates a variety of
responses with different microbes in nature. ―Depending on the species of different
microorganisms, the responses [to As] could be chelation, compartmentalization,
exclusion, and immobilization‖ (Tsai, Shen-Long 2009). Tsai working with Singh and
25
Chen have conducted several in depth studies on Saccharomyces cerevisiae in relation to
As. S. cerevisiae has two different mechanisms to reduce As toxicity (Tsai et al., 2009).
Arsenic uptake by Saccharomyces cerevisiae occurs through three
different transport systems. The pentavalent arsenate, because of the
similarity to phosphate, is taken up through a phosphate transporter. In
addition, two transporter systems for the trivalent arsenite have been
identified. (Tsai et al., pg 662)
This is one example of the complex of interactions microorganisms can have in relation
to heavy metal remediation. There are so many types of microorganisms interacting
within the soil and each different species has a different response to each element.
Saccharomyces cerevisiae is a fungal yeast that is selective for monovalent metal
ions meaning metals that are found with only one electron available for bonding.
Saccharomyces cerevisiae have also been found to be able to live after ingesting high
amounts of As. Certain genes have been identified in S. cerevisiae that are related to the
resistance to arsenate and arsenite (two common species of As). When these genes were
removed (documented as ACR3) there were increased arsenite sensitivities and an
increase in arsenite accumulation in the yeast. Therefore, in this research S. cerevisiae
would not be beneficial in accumulating the heavy metals into itself and transporting it to
the plants because genes block the accumulation of the arsenite, but might increase
uptake by plants by being able to survive in soils with high As content aiding in the
growth of the plants (Ghosh et al., 1999).
Microorganisms form relationships between plants and the surrounding substrates
in order to exchange necessities providing the plant with the nutrients it needs while, at
the same time, providing for the microorganisms. ―Typically, microorganisms are
responsible for providing hormones, nutrients and minerals in a useable form to the plants
via the root ecology‖ (Woodward, p.2). When microbes are found within plant roots and
plant rhizomes they are called rhizobacteria. ―The presence of rhizobacteria increased
concentrations of Zn (Whiting et al., 2001), Ni (Abou-Shanab et al., 2003b) and Se (de
Souza et al., 1999a) in T. caerulescens, A. murale and B. juncea, respectively.‖ (Jing)
Here Jing is illustrating how plants necessary elements are provided for by the presence
of these microorganisms
26
Lactobacillus is a specific species of microbes that creates lactic acid and are
known as LAB. These bacteria can also live in environments containing high amounts of
heavy metal contamination. ―Results of metal resistant ability also implied that tested
LAB can easily survive with high As and Pb containing environment ―(Bhakta, 2010).
The Lactic Acid bacteria mentioned here were found to be specifically Pediococcus
dextrinicus and Pediococcus acidilactici which were not used in this study, but this
information was released after the application of the BioKleanTM® the microorganism
blend used for this study. LAB are very common in the soil/plant realm. ―[L]actobacillia
are ubiquitous, present on the surface of all living things and especially numerous on
leaves and roots of plants growing in or near the ground (Fallon, p 89)‖. They aid in plant
growth and help maintain plant health.
As discussed previously in the biochar section, pore size and distribution are
important factors within soils in order to maintain healthy ecosystems for microbes also
determining the amount of water and air content important for life (Murányi, p3 ).
Conditions within the soils are very important for successful microbrial inoculation. In
polluted environments, root systems may be restricted due to low nutrient content and
availability decreasing the success of the microbial inoculation. By introducing
microorganisms into a polluted environment, root growth will likely increase and create a
healthier environment for plants. ―An efficient microbial inoculum generally increase the
vitality of the soil / plant interface (Murányi, p4)‖. Due to the need for a successful
inoculation that can withstand high levels of As and Pb, a particular microorganism
brew/culture was selected for this research.
With this background on smelting pollution and phytoremediation the goals of
this study are better understood. Bioremediation is very site specific and greatly depends
on the soils present. The next chapter will provide more in depth information on
bioremediation specific to the Vashon Island site.
27
CHAPTER II Bioremediation Specific to Vashon Island
The Home Remedy Study Site
The study site was provided by resident Amy Wolf who lives on 2 acres on the
southern end of Vashon Island. Two accessible areas on the property were used. One was
a grassy side yard used previously for gardening, called the grassy area, where all the
trees had been cut down in the early 60s. The other location is located in the back yard
and will be referred to as the ―previously forested area.‖ This is a newly cleared area
prepared a few months prior to the onset of the project. Both areas contained
concentrations of Pb and As above Washington State and EPA allowable limits. These
initial values were obtained onsite using a Niton XRF field analysis instrument with an
environmental toolkit.3 These values were confirmed later using an in lab method (See
Chapter 4, Table 4).
Figure 5. Map of Vashon Island Site Location
________________________________________________________________________
3. This analysis was conducted by myself (Shannon Clay) and Andrew Long, a project
constituent.
28
The grassy area was covered in Dactylis glomerata (orchard) and Festuca sp.
(fescue) grasses. The underlying soil is a humic sandy loam with hydric areas. A visible
horizon appears during the rainy season (winter), which seems to delimit soil-gas
penetration by means of a fluctuating water table. Other spots within this same area had
more of a clay composition with a sandy loam top soil with hydric limits. The soil pH
ranged between 6-6.5. The previously forested had Psuedotsuega menzesii (douglas fir),
Alnus rubra (red alder), with an understory association of Pteridophyta including Pteris
munitum (western sword fern) Pteris aquiline (common bracken fern), Vaccinium sp.,
Gaultheria. shallon (salal) and Ribes sanguineum (flowering red currant). The soil in this
location has a 1inch deep, of humus and detritus. The soil is a loamy sand. pH varies
slightly, averaging 6. Over the last 5 years rain fall in this area averaged around 46
inches annually4. The trees all around the site are 15m(50ft) –27m(90ft) tall. Insolation is
more limited in the spring and fall by canopy height. Summer sun is ample because the
location of trees does not shade those areas.
Restoration at this site is aimed to test practical methods for bioremediaton of As
and Pb in soils. After researching possible plants and soil amendments three applications
were chosen. These were applied together and separately to determined individual
impacts and possible synergistic effects. Brassica juncea, brown mustard, was chosen for
the plant, a microorganism blend called BioKleanTM as well as a soil amendment called
biochar were chosen to aid in sequestration of As and Pb by B. juncea.
Phytoremediation with Brassica juncea
There are many candidates for phytoremediation of this site including Sunflowers,
sea purslane, and ferns. Sunflowers (Helianthus annuus ) may have been a better plant to
use in an area that has more sunlight than this study site. However, in some research
sunflowers, did not accumulate as much As as Brassica juncea (Scholtz, 2006). Pteris
vittata, common name Chinese brake fern, is a well known accumulator of As but is not a
Pb accumulator. It could be possible to use the fern in a rotation with another plant that
accumulates Pb. More information about P. vittata can be found in Chapter IV
________________________________________________________________________
4. Tahlequah rain gauge data from King County precipitation data
29
Furthering the Research. Hyperaccumulators, such as sea purslane, grow slowly
especially when contamination is high (Jing et al.) Sea purslane is a small plant and in
soils that have more sand than the soils on Vashon Island. Many plantings and harvesting
would be needed for sea purslane because of its size.
Brassica juncea (Brown Indian Mustard) was chosen for a number of reasons.
Particular emphasis has been placed on the evaluation of shoot metal-accumulation
capacity of the cultivated Brassica (mustard) species because of their relation to wild
metal-accumulating mustards (Raskin et al. citing Kumar et al., 1997). Even though B.
juncea has a lower metal accumulating capacity than sea purslane for example, it has
higher growth rates. These growth rates may allow for more biomass to be harvested and
an overall greater amount of the contaminants (Kumar et al.,1997).
For the remediation of the heavy metals As and Pb, B. juncea has been found to
remediate both through hyperaccumulation and phytoextraction successfully (Salido,
2003, Kumar et al. 1995). One article found Pb to be accumulated around concentration
levels of 25mg/g of Pb per plant in the roots alone (Clement et al., p50 2005). Cultivar
426308 of B. juncea was found to be the best Pb accumulator by Kumar et al. while
cultivar 211000 was found to be a good accumulator for As by Scholtz during his thesis
work on Uranium contaminated soils. These and other B. juncea seeds were requested
from the United States Department of Agriculture (USDA) National Plant Germplasm
System (NPGS part of the Germplasm Resource Information Network GRIN). These
specific species had research finding these species to accumulate As and Pb. However, in
order to maintain the collections NPGS only allows 200 seeds of any variety to each
individual request. This amount of seed would require an extra year to prepare for the
study in order to grow these plants to harvest there seeds. At least 1200 seeds are needed
for this study. More information on these seed cultivars can be found in the Appendix.
An available varietal species of Brassica juncea was chosen for the research from
FEDCO seeds. 3232PO Pung Pop Mustard Gene Pool OG (40 days) was chosen because
it was known to grow large leaves and thick stalks in a short period of time. This would
likely lead to amassing more As and Pb. The varieties‘ description reads as follows:
Open-pollinated. Brassica juncea Pung Pop is an acronym for Pungent
Population, a gene pool Morton selected out of breeding populations from
Miike-Horned crosses, pungent Indian mustards. The results are rapid-
30
growing large plants with thick stems, big dark green leaves and handsome
red veining...Survived Roberta‘s overwintering trial. OT-certified. (FEDCO)
In addition to being rapid and large growing, this variety was also hearty enough
to overwinter providing more accumulation time. Any quantity could be obtained
by any one allowing this variety to be easily accessed by other‘s who would like
to do remediation in their yards.
A major issue with using B. juncea realized through in situ studies was
that the shoot metal accumulation in plants grown hydroponically as well as in lab
controlled conditions accumulated much more contaminants than B. juncea grown
in the field. This phenomenon is explained by the low bioavailability of heavy
metals in soils (Raskin, 1997). In order to make the metals more bioavailable,
chelation can be used. Illya Raskin headed numerous research studies using
chelation to enhance Pb uptake by B. juncea.
Vegetation growing in heavily contaminated areas often has less than
matrix][Cunningham et al. 1995]. Even plants that have a genetic
capacity to accumulate Pb (e.g. B. juncea) will not contain much Pb in
roots or shoots if cultivated in Pb-contaminated soil. The solution to
the metal availability problem came with the discovery that certain
soil-applied chelating agents greatly increase the translocation of
heavy metals, including Pb, from soil into the shoots [Blaylock et al.]
(Illya Raskin, 1997)
The application of chelators may be the key to successful phytoremediation for heavy
metals. Some metals are adsorbed to oxides, but these bonds can be broken releasing the
metals through natural and applied chelates, or the increase of cation and anion exchange
rates. The soil composition will determine the soil ecosystems ability to allow
movements within the soil. The amount of clay and organic matter, as well as the texture
and cation exchange capacity (CEC) within the soil will influence the migration of the
metals (Mason, 1992).
Application of Biochar at the Home Remedy Site
In using biochar at the Home Remedy Site, it was not clear how the biochar
would interact with the mustard plants, microorganisms, and soil in metal accumulation
31
within the plants. The intended purpose of using the biochar was as a soil amendment to
increase cation and anion exchange and water retention for the mustards while providing
nutrients for the plants as well. This would aid the plants by providing necessary
nutrients, lengthening their root systems and being able to access more of the heavy
metals. It was also theorized that it would benefit the microorganisms being applied in
some of the same plots. The proposition used in biochar application for this study is that
the biochar will aid in the metals movement toward the plant through microorganism
plant relationships occurring around and within the biochar.
An apple tree (malus sp.) was the feedstock pyrolyzed for the research. This is a
good biomass source for the Pacific Northwest because they are common and because the
sapling branches often are trimmed yearly providing a locally abundant source of
feedstock for making biochar. Britton Shepard, founder of Renata Biochar Systems,
provided access to his kiln in Fall City, WA to produce our biochar. The kiln is styled as
a 2 door steel retort. The feedstock was pyrolized at temperatures between 500-700° C
using chopped wood as the fire and heat source. On the removal of the biochar from the
kiln it was immediately dipped into a barrel of water to prevent further burning and to
reduce the heat to a manageable level. The biochar was then pulverized into smaller
pieces using a grinding machine. It was distributed into the plots by tilling at a rate of
20tons/hectaracre equaling 1.5 gallons per plot.
Biochar has been shown to make acidic soils more alkaline when added unless the
biochar is acidic and then it will actually lower pH (Lehman, p. 262). This was a concern
for this research because Pb has been found to be more extractable in acidic soils
(Rieuwert et al. 2006 ) as well as more mobile and sequesterable (Matos et al., 2001,
Udon et al., 2004) (Kashem et al.). As availability has a strong and negative correlation
with pH as well (Luo et al., p5 2008). However, it has been found that inorganic As can
be relatively mobile in soils in both oxidation states, particularly in alkaline soils (Hooda,
p142, 2010). The Home Remedy Site soil is slightly acidic with a consistent pH of 6
when tested with pH strips.
It was hypothesized the biochar would increase the ability for cation exchange
increasing the mobility within the soil and cause the As and Pb to be more available for
accumulation in the plants. This would occur because of biochar‘s surface sorption
32
abilities breaking soil bonds and forming new bonds within the biochar. When the bonds
are breaking in the soil the metals may become more available during that time. Also,
with the addition of microorganisms that can form chelates around heavy metals, biochar
can react well within these chelated environments sorbing the chelates (Lehman, p.263).
Then the Pb would be available to certain microorganisms that may transport it to the
mustard plant roots. Even though the concentrations of extractable As and Pb are likely to
increase from adding biochar, the amount accumulated by the plants might decrease
because of the affinity of the heavy metals to the surface of the biochar (Namgay,
Abstract 2010). Biochar will likely attract the heavy metals within the soils to its surface
and could result in a decrease in available Pb and As because it is bound to the biochar. It
is hypothesized that microorganisms could facilitate uptake of these non-bioavailable
metals into plant tissues while biochar makes the metals in the soils less bioavailable and
less toxic but still provide an environment where these metals could be permanently
removed by plants.
Application of Microorganisms at the Site : SCD BioKleanTM
BioKleanTM was chosen for use to aid the growth of the mustard plants and in the
accumulation of metals. This brew is made to support itself with bacteria that provide
nutrients and necessities needed for the other bacteria within the brew.
The SCD consortium are ecosystems consisting of balanced populations of
different probiotic strains trained to live together via growth selection, which
in turn translates into balanced metabolic changes of the application
environment. Conceptually, the yeast have the ability to assimilate glucose as
a substrate and produce pyruvic acid through metabolism of the saccharide
decomposed system. Pyruvic acid can be used as a substrate of facultative
anaerobic lactic acid bacteria. In this way, if the lactic acid bacteria using the
metabolite of yeast multiply, the formed lactic acid becomes the substrate of
photosynthetic bacteria and they can be multiplied. Then yeast uses the
saccharides formed by this photosynthetic bacteria as a substrate and can
multiply repeatedly. This implicates that the microbes in SCD Probiotics
Technology continue to aid each other to keep alive and stay strong in the
environment. The lactic acid bacteria (LAB) produce lactic acid as the major
metabolic end product of carbohydrate fermentation. LAB are also
characterized by an increased tolerance to a lower pH range. This enables
LAB to outcompete other bacteria in a natural fermentation, as they can
withstand the increased acidity from organic acid production. Through the
metabolism of LAB, CO2 (carbon dioxide) is formed. This is used by other
33
species in the consortia as a source of energy to their own metabolic systems,
e.g. phototrophic bacteria. These cultures synergistically work to inhibit the
growth of pathogenic harmful bacteria through competitive exclusion. In
addition, the product contains metabolites produced by the consortia of
beneficial microbes and the chemical characteristics of these metabolites
contribute to antimicrobial properties, neutralization of toxic substances as
well as contribute to health benefits.
For this feasibility study, this culture/blend of microbes were applied in order to aid
plant growth, transport of the arsenic and lead, as well as create relationships between the
plants, soils and biochar. The microbial brew chosen for this research was easily
accessible at reduced costs already prepared and it contains a few microorganisms shown
to aid in the remediation of heavy metals while benefiting to the plant growing process.
The microbial content is based off of the microblends called EM (Effective
Microorganisms) discovered in Japan in the 1970‘s. This specific culture has been shown
to increase agricultural yields of a variety of crops especially when used in combination
with other soil amendments (Hussain et al., 1999). Studies also identified greater
resistance to water stress (Xu, 2000) and a better penetration of roots (Ho In Ho and Ji
Hwan, 2001). The effect of EM on test white mustard (Sinapis alba) seeds was studied in
a germination experiment of four days. EM vitalized the germination, because the
average shoot length was increased by 25% (muryani, p. 10). This would be helpful in the
faster accumulation of heavy metals. EM helps to re-establish a balanced soil ecology and
to combat oxidative corrosion in plants and humans (Deiana, Dessi, Ke, Liang, Higa,
Gilore, Jen, Rehan, Aruom, 2002)
SCD BioKleanTM is a specialized EM culture of microorganisms used more
specifically for cleaning a wide variety of surfaces and contaminants, but it is also greatly
used for the treatment of polluted water and solid waste. It has been created by SCD
(Sustainable Community Development) along with other probiotic brews to aid in the
responsible care of ecosystems. Mainly, for this research the use of BioKleanTM is aimed
at aiding in plant growth in heavy metal contaminated soils. Following is the list of
microorganisms in SCD BioKleanTM:
Bifidobacterium animalis, Bifidobacterium bifidum, Bifidobacterium longum,
Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus bulgaricus, Lactobacillus
34
fermentum, Lactobacillus. plantarum, Lactococcus lactis, and Streptococcus
thermophilus, Saccharomyces cerevisiae, Bacillus subtilis, Rhodopseudomonas palustris
and Rhodopseudomonas sphaeroides
Below is more information about each type of microorganism in the brew to help explain
how each can contribute to the bioremediaton process.
Bifidobacterium spp.
Bifidobacterium sp: human gut microflora that control pH by producing lactic and
acetic acids. Also helps to control pH of soils.
Bifidobacterium animalis, Bifidobacterium bifidum, Bifidobacterium longum
Lactic acid bacteria (LAB)
Lactobacillus spp. Are used as the general substrate for growing the other
microorganisms in the culture. They are acid tolerant bacteria that all produced
acetic acid and lactic acid during fermentation and inhibit yeast growth while
improving aerobic stability. ―Lactate fermentation facilitator as being obligate
heterofermenter‖(Microbial Consortium Mechanism) These bacteria are known for
their ability to make ATP from sugar and milk.
Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus casei,
Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis,
Streptococcus thermophilus
Yeast
Saccharoyces cervisae; as discussed earlier this yeast has a particular ability to
transport As without dying. It‘s role within the microorganism brew is creating
movement and aeration while also providing food for other microbes.
Gram-positive spore forming bacteria
Bacillus subtilis var-anti fungal and the phototrophic bacterium that produces
proteolytic enzymes. These enzymes break down proteins into amino acids.
35
Probiotic benefits and co-growth promoting the mucus layer secretion by other
microbial strains and production of beneficial enzymes.
Photosynthetic bacteria
These help to create biomass from sunlight to feed other microorganisms.
Rhodopseudomonas palustris- phototropic bacteria that converts sunlight to cellular
activity and converts CO2 to biomass and fixes nitrogen (R. palustris citation) It is
found in soils and water and makes its living by converting sunlight to cellular
energy and by absorbing atmospheric carbon dioxide and converting it to biomass.
This microbe can also degrade and recycle a variety of aromatic compounds that
comprise lignin, the main constituent of wood and the second most abundant
polymer on earth. It grows both in the absence and presence of oxygen.
R. sphaeroides- phototropic- fixes nitrogen
SCD Probiotics products activity can consume and also mobilize nutrients. When
former researchers have measured the chemical composition of the solution phase by
ICP, The concentration of macroelements (Ca, Mg, Na, K) did not change significantly
from before to after inoculation. However, Phosphorous and Manganese decreased.
…the original P concentration (34 mg/L) decreased down to 17 mg/L,
what was caused by the P consumption of growing microorganisms. The
Mn concentration decreased down to a minimum value then started to
increase back again. The Cu concentration decreased continuously,
indicating that this element was needed for microbial growth (Muryani
p7).
SCD Probiotics products have shown to be highly efficient increasing biological activity
within soils and maintaining the level of activity for long periods of time.
SCD Probiotics are also more acidic and causes decrease in soil pH during
microorganism activation. This usually occurs by a factor of .9pH units (Muryani, p. 3).
Acidic soils are better for Pb and As movement and phytoaccumulation (Luo et al., 2008;
Bienfait et al., 1986)
36
BioKleanTM and other SCD Probiotic brews provide a controlled environment
preventing molds and other harmful bacterias that cause plant and animal diseases.
Working together, the microorganisms within the brew keep each other alive while
keeping non-beneficial microbes away.
Antimicrobial capacity of SCD Probiotics products has been evaluated and
challenged with a large variety of unpleasant microorganisms, including
bacteria (e.g. Escherichia coli, Pseudomonas aeruginosa, Salmonella
typhimurium, and Staphylococcus aureus), yeast (e.g. Candida albicans),
and mold (e.g. Aspergillus niger, and Fusarium oxysporum). Accordingly,
the outcomes from the antimicrobial testing confirm that SCD Probiotics
products are capable of controlling and reducing the growth of unfriendly
microorganisms efficiently. (SCD Probiotics, 2008)
SCD Probiotics, in collaboration with other labs, show the ability for their microorganism
brews to fight off these unwanted bacteria and fungus. Pseudomonas aeruginosa is
commonly found in soil, water, human skins, and medical devices. It is a typical cause of
infections in pulmonary tract, urinary tract, burns, wounds, external ears and also blood.
Aspergillus niger is a fungus, usually causing black mold disease on fruits and vegetables
(e.g. grapes, peanuts, and onions). In addition, it is a general cause of fungal ear
infections in human. Fusarium oxysporum is a fungus, usually causing Fusarium wilt
disease (Panama disease or Agent Green) in plants. SCD Probiotic brews prevent these
unwanted funguses and molds creating a safer growing environment for plants and other
bacteria and a safe working environment for humans. This means it can safely be used in
the global environment.
Research Questions and Hypothesis
With these three bioremediation applications; Brassica juncea, Biochar and
BioKleanTM, the Home Remedy Project Feasibility Study will examine the ability for the
amendments to work together in order to help the B. juncea grow well for
phytoremediation. The microbial brew will aid the plant in its growth and help assimilate
the Pb and As contaminants as the biochar is chelating the minerals slightly by increasing
cation exchange, providing nutrients to the mustard plants, and providing substrate for
the microorganisms.
37
This thesis will address the following hypotheses. The main hypothesis being
tested in this feasibility study is that soils will show a significant decrease in heavy metal
concentrations of As and Pb from the bioremediation treatments. Another hypothesis
being tested is that the guild with all three elements working together will result in the
greatest decrease in Pb and As concentrations.
38
CHAPTER III Materials and Methods
This chapter outlines and explains the materials needed for the methods chosen to
perform the feasibility study in situ over the spring and summer of 2011.
Overview
With the assistance of volunteers interested in the study, the soils were prepared
for the experiment by tilling. These individuals also assisted in monitoring the site over
the growing season. The general experimental approach was to apply various As and Pb
bioremediation treatments and determine after one growing season if they decreased
metal concentrations in the soils.
The following is a list of the materials and a description of the methods used in the
feasibility study.
Materials
XRF Analyzer
Random number generator
Gloves specific to site
String
pH strips
Log book
Stakes
Large stakes for fencing
Dry storage area
Broad fork
Deer fence
12 cup glass measurer
Plastic spoons
Shovel
BioKleanTM
Measuring tape
Dionized Water
4 rain barrels
Cardboard bowls
irrigation lines
Water source
4 oz glass jars
Attachments for drip line to barrel
Drip nozzles
Rain gauge
Experimental Design
To select the sites for the experimental plots, the most contaminated locations
within the study site were located. A Thermo Scientific Niton XRF Analyzer with an
environmental analytical tool was used to obtain As and Pb measurements in the soils.
The locations chosen for test plots contained 30ppm-200ppm As and 0 ppm-548 ppm Pb.
The highest concentrations were found on recently cleared forestlands within the study
39
site. Sixteen one square meter plots plus two control plots were defined using string and
stakes within the highly contaminated areas. Eight plots were located in the previously
forested area and another eight were located in the already cleared grassy area. There was
one control plot in each area, one for the previously forested area and one for the grassy
area. Then the sod was removed and the plots were tilled down to seven inches using a
broad fork. Only seven inches were tilled because the metal contamination decreases
between 6 inches (15.24cm) down to 12 inches (30.48cm) and there is no contamination
usually found below 12 inches (Glass et al., 2000). Soil samples were then collected for
the initial soil heavy metal concentration after the soil was homogenized/mixed by tilling.
At each plot, soil samples were taken randomly at each depth. Plastic spoons were
use to collect the soil with a new one used for each sample. Each 1 m square was divided
into a 16 square grid using a piece of string. A random number generator was used to
determine which square within the grid was sampled from without repeating the same
square for the same depth. Three samples were taken randomly at 2 inches deep and three
samples were taken from 6 inches deep within each plot. The three random samples were
mixed together in a cardboard bowl (one bowl for each depth) and then 4 ounces were
sub sampled into a glass jar for the subsequent analysis in a professional lab. This was
repeated for each depth taking three samples at 2 inches, combining in bowl, and three
samples at 6 inches, combined in own bowl, for all 16 plots and the two control plots
producing two samples for each plot for a total of 36 samples.
The samples were analyzed by Freidman and Bruya, Inc. in Seattle, WA.
Friedman and Bruya is a company that conducts analysis of organic and inorganic
compounds using federal and state approved methods. They are accredited by the
National Environmental Laboratory Accreditation Program for metals testing, the
Washington State Department of Ecology, Oregon Department of Environmental Quality,
and the California Department of Health. At the lab the samples were further
homogenized, while removing larger particles with a .10 mm screen. Each soil sample
was chemically digested using EPA method 200.8/6020 to be prepared for analysis with
an Inductively Coupled Plasma Mass Spectrometer (ICP-MS). Due to a
miscommunication with Friedman and Bruye total As and Pb concentrations were not
measured using the total metals method 200.8 as desired. Thus, only recoverable, not
40
total, metals were measured. The consequence of not having the total metals within the
soils is that there is no way to know if metals decreased because they became insoluble,
but remained in the soils.
Experimental Treatments
The three different amendments (mustard plants, Biochar and BioKleanTM), in
different combinations were distributed amongst the plots. One gallon of biochar was
poured, using a gallon bucket, and then tilled into eight plots, four in the grassy area and
four in the previously forested area. Then Indian Mustard, Brassicae juncea Pung Po Pop
Mustard seeds were planted in every plot (except the two control plots) in rows 1.5 feet
apart and each seed 1‖ apart and 1‖ deep. This allowed three rows of plants to fit in each
plot. One week later a drip irrigation system was installed and eight plots were inoculated
with the SCD BioKleanTM. Microorganisms were applied weekly at a rate of 450 ml per
plot every week until harvest of the mustards (around 10-14 weeks). The microbes were
diluted and activated by putting 1:50 parts water in two of the four 55 gallon barrels.
Each barrel was connected to four plots and once a week 7.6 cups SCD BiokleanTM were
diluted with 23.75 gallons of water. This approach delivered water or the inoculant to the
4 plots connected to the barrel at a rate of two gallons/hour for a total of 450mL
BioKleanTM per plot per week. The two barrels without microorganisms delivered only
water. A mark was made on each barrel to represent the 23.75 gallon line after the first
inoculation to maintain proper measurement.
The research plots were organized into groups of four. Two plots in each set
contained biochar and mustards, while the other two contained only mustards. Each set of
four plots was watered by a rain barrel with two of the barrels delivering the
BioKleanTM microbrew. Thus, a total of four plots contain BioKleanTM, Biochar and
Mustards, four contain BioKleanTM and Mustards, four are treated with Biochar and
mustards, and four have only mustards.
41
Figure 5. Distribution of Amendments
This chart diagrams the distribution of amendments to the plots and what each plot
consisted of.
These plots were monitored while the two control plots were sampled every 6
weeks to determine the natural variation in the soil metal concentration over time after
being tilled. A deer fence was erected around both locations to prevent animals from
eating mustards and interfering with the plots.
When the rain barrels containing BioKleanTM were inoculating the soils, the other
two rain barrels were delivering the same amount of water to the un-inoculated plots.
Watering was monitored by the residents to ensure plots were being watered weekly.
During dry times, a protocol was followed to provide extra water for the mustards. To
make sure each plot received the same amount of water, the rate at which the water left
the hose was kept equivalent throughout the watering process by watering each plot for 5
seconds and turning the hose on to maximum. Watering occurred only in the morning or
in the evening to avoid mid day evaporation. A water resistant journal was kept on site so
all participants could note observations and activities at the site. Rain meters were placed
at both of the sites to monitor average rainfall.
The mustards were thinned two weeks after sprouting. The plants were monitored
until they began to bolt. Harvesting the plants occurred when they bolted but before they
began to grow seeds. All of the plant matter, roots, shoots and flowers were kept and
42
stored in a refrigerator at 4°C. The plants were dried and tested for the amount of Pb and
As accumulated in the roots, and above ground biomass. This testing was conducted
using the Niton XRF. A final sampling of the soil was collected , using the same transect
sampling methodology mentioned prior, after 2-3 rounds of plants are harvested before
the first winter freeze. All of the soil samples were sent to Freidman & Bruye. All the
sampling procedures appear in the appendices while the 200.8 EPA method can be found
online using Google search. The sample test results were then compared for before and
after concentrations using a both a paired t-test and the Wilcoxin Signed Rank Sum Test
to test for significant differences.
43
CHAPTER IV Results and Discussion
This chapter provides the results of the study followed by a discussion on the
obtainable results.
Observations of mustard plants over the growing season
Seedlings sprouted two weeks after being planted. They grew slowly and did not
start producing adult leaves for another 2 weeks. Three and a half days later over half of
the plants were missing with little sign that plants ever grew in half of the plots. In a
couple of the plots short, one or two broken stems could be seen barely rising above the
ground. It is possible that these broken stems are evidence of animals eating the plants.
Often plants that are weaker or not healthy are eaten by insects or other grazers. Even
more interesting was the realization that the only surviving plants were in plots
containing biochar. All plots containing biochar still had living mustards except for one
(1F4). Table 4 displays the number of mustards surviving in each biochar plot. This
suggests that the mustards would have not survived without the biochar. More mustards
Table 4. Number of surviving mustards per plot
(only plots with biochar)
Previously
Forested Plots
2F1
2F2
2F7
2F8
# of Mustards
51
48
9
32
Grassy Area
Plots
1F1
1F4
1F7
1F8
# of Mustards
2
0
21
10
were growing in the previously
forested plots than in the grassy area
likely due to the clay soils in the
grassy area. The mustards did not
flower for another 6 weeks and some
not until 7-8 weeks. They grew to be
on average 54.86 cm (1.8 feet) tall including the flowering body.
After the first living plants were harvested in weeks 7 and 8, a second round of
mustards were planted. The same die off happened when the first mature leaves were
beginning to form leaving only living mustards within the plots containing biochar
(excluding 1F4, an all clay soil) supporting the idea that the mustard survival was due to
the biochar. Mustards did not grow large leaves or grow quickly in this study. This may
be due to the inclement weather patterns for that growing season. Due to the slow growth
of the mustards only 2 rounds of mustards were planted before the first frost.
44
Soil Sample Analysis Results
Initial soil samples were collected May 25th, 2011 and after treatment soil samples were
collected September 24th, 2011. The results of the soil sample analysis for As and Pb
concentrations appears in Table 5.
Table 5. Soil Samples of Arsenic and Lead Concentrations in ppm
Initial After Initial After Initial After Initial After
Plot 2in As 2inAs 6in As 6inAs 2inPb 2inPb 6in Pb 6inPb Treatment
1F1 58.6
64.2
68.0
72.3
78.9
70.8
120
75.3
B, K, M
1F2 41.4
71.2
31.5
48.9
81.7
104
47.1
60.5
K, M
1F3 75.5
58.5
57.1
81.5
103
101
69.2
80.5
K, M
1F4 73.3
64.9
72.1
33.3
131
42.8
106
25.8
B, K, M
1F5 47.1
69.1
29.0
54.2
60.2
113
44.9
81.0
M
1F6 51.0
36.5
51.6
31.2
86.9
46.2
101
41.8
M
1F7 34.3
49.1
41.2
92.6
55.7
58.3
61.5
85.6
B, M
1F8 45.9
35.6
91.2
43.6
91.3
50.2
180
66.2
B, M
1FC 44.2
37.6
29.1
32.5
65.9
51.2
47.9
48.5
Control
2F1 125
119
135
107
477
223
156
148
B, M
2F2 170
72.5
125
111
552
113
169
136
B, M
2F3 120
86.0
79
81.7
187
172
92.8
166
M
2F4 72.3
126
134
56.0
167
219
296
67.9
M
2F5 104
112
97.1
65.8
162
213
107
86.1
K, M
2F6 156
117
103
54.7
214
172
106
83.4
K, M
2F7 105
100
77.6
54.8
313
193
145
63.4
B, K, M
2F8 48.2
106
68.7
67.0
75.9
159
117
108
B, K, M
2FC 125
69.4
107
78.8
180
155
182
65.6
Control
TM
B=Biochar K=BioKlean
M=Mustards
= contained living plants
This table displays not only the heterogeneity of the soils, but also the patterns of
increase and decrease of As and Pb within the sixteen test plots and the control
plots.
Variability of Pb and As
Overall, As and Pb soil concentrations showed large variability before (As =
81.33mean ± 37.7 standard dev. Pb=145.56 mean ± 111.20 standard dev.) and after ((As
= 71.13 mean ± 27.33 standard dev. Pb= 104.06 ± 55.98 standard deviation) treatment
indicating large heterogeneity in the soil composition. There was also significant
variation in the direction of the change in metal concentration over time. Both increases
and decreases in As and Pb concentrations were observed over the study period. Increases
of metal concentration were unexpected and suggest processes transporting metals into
45
the site, such as movement by insects or complex processes like microorganisms
unbinding metals allowing for their transport. Because only recoverable metals were
measured, it is also possible that microorganisms changed the metals to become mobile
or immobile where the total concentration is not actually changing but simply becoming
unavailable for counting within the lab process used by Friedman and Bruya, Inc.
because the metals are now insoluble.
Differences Before-After Treatment
The main hypothesis being tested was that there would be a significant decrease
in As and Pb concentrations within the soils following the treatments. Only plots treated
with Biochar+mustard and Biochar+ BioKleanTM +mustard showed a significant decrease
in Pb when using a(p= 0.013, paired t-test). There were no significant decreases in As
concentrations. Due to the small sample size and the possibility that the data was not
normally distributed, the nonparametric Wilcoxon Signed Rank Sum Test was also
conducted to test for significant differences. The results confirmed that there was a
significant decrease in Pb in plots treated with Biochar+ BioKleanTM +Mustards (p=
0.006 and with Biochar+Mustard (p= 0.025).
Control Plots Over Time
The control plots also showed high variability of As and Pb over time (Table 6).
Table 6. Time Series Control Plot Results
Control 1F Early June July August Late September
44.2
35.0 33.0
37.6
As @ 2”
29.1
33.4 36.0
32.5
As @ 6”
65.9
50.1 45.0
51.2
Pb @ 2”
47.9
50.6 44.0
48.5
Pb @ 6”
Control 2F Early June July August Late September
125
102 93.0
69.4
As @ 2”
107
84.6 95.0
78.8
As @ 6”
180
116 89.0
115
Pb @ 2”
182
42.6 75.0
65.6
Pb @ 6”
They showed an overall
slight decrease overtime
in concentrations of both
As and Pb. The control
plot in the grassy garden
area stayed relatively the
same for both As and Pb
whereas the control plot
in the previously forested area decreased in total Pb and As concentration, however, this
decrease was not statistically significant. Figures 4 and 5 illustrate these changes over
time using a line graph. It can be seen that the previously forested area has an initial
46
higher concentration of both As and Pb. After the controls are tilled both drop in
concentrations of As and Pb while the previously forested area decreases more than the
garden grassy area but still remains with higher concentrations by the end of the season.
Figure 6.
Change in Heavy Metal Levels in Previously
Forested Control Plot over 4 Months
Concentration in ppm
200
150
As 2in
Pb 2in
100
As 6in
Pb 6in
50
0
Sam ple
Figure 7.
Change in Heavy Metal Levels in Garden
Control Plot over 4 Months
Concentration in ppm
70
Figures 5 and 6
illustrate the
changes in As and
Pb concentrations
over the four
months of
mustard growth.
The forest plots
had a more
significant change
most likely due to
be disturbed for
the first time since
the contaminated
ashes fell. The
range (0-200ppm)
is different from
the grassy area
because of this
large difference
where the grassy
area did not have
as significant of a
difference between
the first month
and the last month.
60
50
As 2in
40
Pb 2in
30
As 6in
20
Pb 6in
10
0
Sam ple
47
Using the Niton XRF Analyzer to test the dried plant samples, no traces of As or
Pb were found. Therefore, the plants did not accumulate As or Pb in their roots, shoots, or
flowers.
Summary of Results
The experiment examined whether the applications of the B. juncea mustards, the
SCD BiokleanTM, and biochar would significantly decrease the amounts of As and Pb in
the soil over one growing season and whether different combinations, specifically the
guild with all three treatments, would be more effective than the treatments individually.
The results indicated the biochar was possibly the key component needed for the
mustards to grow and the biochar also was associated with reduction of Pb in the soil.
Below are interpretations of these results within the discussion section.
Discussion
Mustard Survival
It is unclear why mustards did not do well and why the ones growing in biochar
survived. There are a few possible explanations for this result. Evidence of slug activity
from the remaining plant stems suggested predation, but in other plots, there was no sign
at all that the seedlings were ever there. Thus, it is unlikely that slugs were responsible
for all the mustard mortality. This growth pattern occurred twice, with the seedlings all
dying in the second round of planting in plots without biochar even when there was
substantial rain. It is possible that the biochar provided the mustards with necessary
nutrients for growth that were not present in the other plots
There are many possibilities as to why the mustard plants grew better in some
plots than others. The plants sprouted within all of the plots, but the only ones that
survived after week 4 were found in plots that also contained biochar. The week when the
first planting of mustards were maturing was particularly dry. Mustards thrive in welldrained moist soils. The grassy area does not drain well whereas the previously forested
area does. Biochar could have retained more water, provided better housing for the
microorganisms to aid in growth, as well as provided phosphorous. Another possibility is
48
that the biochar immobilized the As and Pb creating a non-toxic growing environment
allowing those plants to grow while the others sequestered the As and Pb in a toxic form.
Often used as a soil amendment to aid plant growth, phosphorus (P) could have
been added to the plots but researchers show that this addition results in the formation of
insoluble complexes with heavy metals causing them to become immobile in the soil and
less likely to be accumulated by the plants (Raskin et al. 1994 United States Patent).
There is actually substantial research showing P as a way to immobilize Pb for many
years (Yang et al., 2007). This was not desired for this research, but could be applied if
immobilization is the desired affect.
Another observation showed that the plots with biochar in the forested area had a
much higher plant growth rate when compared to the plots with biochar in the grassy
garden area. Mustards thrive in well-drained moist soils. The grassy side garden does not
drain well whereas the previously forested area does. Also, the organic layer in the
forested area may be providing more of the essential nutrients for the plants. ―Plants can
adsorb a varying proportion of their nitrogen and phosphorous needs as soluble organic
compounds. In addition, various growth-promoting compounds such as vitamins, amino
acids, auxins, and gibberellins, are formed as organic matter decays (Brady and Weil
p514).‖ These provide nutrients for plants as well as microorganisms. The amount of
Nitrogen, Phosphorous, and Potassium makes or breaks phytoremediation as plants need
these to grow regardless. The soils in the previously forested area may have been more
optimal for growth being less disturbed and less compacted than the grassy area. The
added biochar probably increased the CEC and allowing these nutrients to be more
available for the plants as well.
Another issue may be lack of sun exposure in the plots. The plants may have not
been getting enough light in any of the plots to grow amply. A possible alternative
suggests that in some situations conducting bioremediation at a bioremediation facility,
even though it costs to remove the soils and replace the soils with ―clean‖ soils, might be
more effective. The contaminated soils could be transported to a location where exposure
to individuals is not as much an issue and plenty of sun is provided. Once treated, the
soils could return to the site or a site with similar biology.
49
Discussion of Bioremediaton Treatment Results
Phytoremediation was not successful in plots without biochar. Because the plants
only survived in less than half of the plots, and only in plots containing biochar, the only
plots were the role of the plants could be assessed were the ones with biochar. However,
plots receiving BioKleanTM need to be analyzed as well because this microbe mixture
treatment also may have an effect on soil metal concentrations. For the biochar plots,
there was a significant decrease (p=0.013, t-test) in recoverable Pb from the soil while no
difference was found for the decrease in As in these plots. This decrease in Pb does not
include Pb that is not recoverable by the standard method 200.8 used by Friedman and
Bruye, which includes metals that are immobilized by the biochar. Therefore, from these
results Pb becoming immobilized by the biochar may not be detected because it is not
―recoverable‖ using method 200.8. The immobilization of metals by biochar occurs
depending on the metals and what forms they are found in the soil. To recover the
immobilized metals additional treatment is needed to solubilize the bound metals (make
available for counting in the ICP-MS, or bioavailable within the environment).
The decrease in Pb in the previously forested plots is possibly a result of tilling.
Even the control plots showed a significant decrease in before and after levels. The
changes of metal concentration over time in the control plots (figures 5 and 6) suggests
there was a reaction within the soils from tilling. The garden area had previously been
tilled and disturbed so the decrease there was very minor while the decrease in the control
plot in the previously forested area is greater because it has never been disturbed. Tilling
can unbind metals that are immobile. Once tilled, the metals become mobile and are able
to move out of the newly disturbed areas (Glass et al., 2000). Due to an observed change
in the control plots in the previously forested area, this could mean that the significant
values found in the previously forested area are significant due to disturbing the soils for
the first time and not due to the actual addition of biochar. However, when looking only
at the first sample taken from the control plots with one taken at 2 inches and one taken at
6 inches before and after treatment, change in Pb contamination was not significant
within the control plot in the previously forested area or the grassy area. The changes
from the initial soil samples and after treatment samples for the previously forested site
50
were significant for Pb (p=.04, paired t-test). This supports the conclusion that the of the
effect of the Biochar was significant.
The grassy area did not show any significant change for either As or Pb when
examining all of the plots combined. The plots with only mustard plants did not show
significant change in either area. BioKleanTM + Mustard did not show a significant
decrease in Pb or As when using Wilcoxin Signed Rank Sum Test or a t-test for either
area.
Other natural factors could be contributing to the movement of the As and Pb.
Soils can be affected by underground water movements as well as the transfer of nutrients
by worms, insects, microorganisms and burrowing animals (Brady and Weil, 2008 p 451
―Soil Engineers‖). Regardless, the As and Pb did show signs of becoming more mobile or
immobilized, or they could also be moving within the soil ecosystem. In order to better
understand what happened to the As and Pb concentrations further research should
include testing of total metals in addition to recoverable metals.
Even though the soils are highly heterogeneous, there are patterns within the soil
samples that show decreases and increases in the same plots suggesting different soil
activity taking place at different places within the plots and between plots. This dynamic
environment is also illustrated by the ANOVA results showing a high amount of
variability within the same treatments. The results indicated no significant differences
between treatment types. Each plot contains a different soil composition adding to the
difficulty of determining if treatments acted the same way in the different locations. Due
to the high variability of the initial and after treatment samples, it is difficult to answer
whether the guild plots worked better or did not work any better than the double
treatment plots.
Due to the small sample size and the heterogenous nature of soils, the data
collected could not be verified to have a normal distribution. Therefore, the nonparametric Wilcoxin signed rank sum test was used in addition to the t-tests. Nonparametric tests are a weaker statistic. Plots containing biochar within the previously
forested area show a significant decrease in Pb when using the Wilcoxon signed ranked
sum test for non-normal data. The result of p= 0.034 is for the previously forested area
biochar plots whereas plots in the grassy area had a p-value of 0.025 for biochar plots.
51
Comparing all plots containing biochar using the Wilcoxon signed rank sum test shows a
significant decrease of Pb (p= 0.004). Plots with biochar+BiokleanTM+mustard showed a
significant decrease as well (p= 0.046). Plots with only the mustard and biochar show a
significant change with reduced Pb (p= 0.018).
The second research hypothesis was that the guild would reduce Pb and As levels
more than the other treatments. There is no evidence to support that hypothesis. Using
ANOVA (single factor) to compare the means of the differences that each treatment
created, there is not enough difference between treatments to show that one was more
effective than the other. This also points out that the plots treated with biochar did not
significantly change the Pb and As concentrations in relation to the other treatments even
though the change within the plots was significant, it is not significantly different from
the other treatments. Overall, these data are limited because of sample size but also
because of the large natural variation in the soils.
Conclusion
This thesis provides a basis of groundwork to further the study of bioremediation
for As and Pb on Vashon Island. The conclusions that can be drawn from this feasibility
study are not robust, but point to possible solutions to the bioremediation of arsenic and
lead. There is optimism in this research that points to the beneficial properties of biochar
and the use of biochar to influence As and Pb within contaminated soils. Further testing
needs to be conducted in order to know whether the Pb is becoming immobilized by the
biochar. If it is immobilized, the use of biochar could be implemented in order to grow
food in a safe environment where the Pb is not bioavailable. This research also illustrates
what does not work in some situations for in situ remediation. Mustard plants, which are
not hard to grow, need substantial amounts of sunlight as well as nutrient available soil. It
is hard to say why the plants in plots with out biochar dissipated, and other plants might
be better suited for Amy‘s backyard ecosystem that are also good at accumulating As and
Pb for harvest.
This concludes the thesis research; the next chapter provides suggestions on how
to improve the approach used in this study. In addition, specific suggestions are made for
future work in this topic.
52
CHAPTER V: Suggestions for Future Research
This chapter provides ways this thesis work could be improved in order to draw
conclusions from more robust research. Even though the thesis work has been concluded,
the contamination still remains. The following discussion offers a critical view of the
thesis work as well as a way to expand the thesis result findings.
First of all, in order to be able to obtain more complete data, a third control plot
in the design would have allowed more statistical accuracy when comparing natural soil
change in the control plots to treated soils in the treated plots. It would be best to have
four control plots, two in each area. Also, in order to carry out a BACI (Before After
Control Impact) Paired test, multiple samples must be taken before and after treatment
where as in this case the samples in the controls were taken with one prior and then 3
during the time period instead of many before and many after (Smith, 2002). BACIP
provides a better way of detecting natural changes to the soils outside of the treatments
and provides a stronger basis for conclusions.
Only metals recoverable by EPA method 200.8 are provided in the results. For
soils, the samples must be diluted and digested. The soil digestions are done using metals
grade Nitric acid, Hydrochloric acid. Ultimately, the results only reveal ―leachable‖
metals. Leachable metals do not necessarily include all metals within the soils. It is also
not completely known whether non-leachable metals are going to be bioavailable when
ingested by humans.
There is a good deal of scientific research that debates whether leachable metals
are equal to bioavailable metals and those that are available for plant uptake. Most
research indicates that the immobile Pb is not toxic even if ingested (Magrisso, 2009;
Miretzky and Fernandez-Cirelli, 2007, Yang et al., 2007). Still more research needs to be
done in order to understand what forms of immobile Pb and As are non-toxic to humans.
Also, it is important to note that the immeasurable, immobile Pb may become mobile
over time and it is very difficult to know how long the Pb will remain bound within the
soils. Even with the Pb bound the contamination is still there, and through time could
become bioavailable. Future research should involve total metals analysis instead of
recoverable metals. This can be done with an additional acid leaching process using
53
hydroflouric acid. Also, it would be best to have tested the plants for any Pb or As
concentrations found within the roots, shoots, leaves and florets to compute a mass
balance for each metal.
How this Experiment Could Be Improved
Enhance irrigation system to be set on a timer. In order for the timers to work barrels
need to be raised higher to create more pressure allowing the timers to work properly.
Find a better plant species. Another mustard species would work better and it would be
best to get more than 200 seeds of the varieties known to accumulate As and Pb. After
seeing the growth of the mustards Brassica juncea it was noted that they did not grow
very large in the leaves or tall in the stems as was expected. It was later discovered in the
book Trace Elements In Soils edited by Peter Hooda, that B. juncea is actually an over
wintering crop. It is to be planted in late fall and flowers in the spring (p330). Thus, a
better plant more suited for growth in the Pacific Northwest is desirable for
phytoextraction.
Broadcast seeds rather than plant seeds in rows.
Do a more in depth search of how to obtain more than 200 seeds of cultivar 426308.
Either ore seeds need to be required or 200 seeds need to be planted and grown to
generate enough seeds to conduct the research.
Look at companion planting with natural chelating grasses. Some grasses can aid in the
mobilization of metals while others actually sequester As and Pb. More research needs to
be done in this area for Vashon to secure high use areas such as parks.
Use a more specific blend of microorganisms created for heavy metal remediation of As
and Pb. Some research suggests that using a blend of microorganisms containing
Pediococcus dextrinicus and Pediococcus acidilactici would be more effective due to
these micoroorganisms ability to change As and Pb bonds within various mediums.
54
Make a more personalized blend of microorganisms for the plant being used. None of the
microorganisms in the microbial inoculant are actually found in the rhizosphere of
Brassica juncea. (Belimov et al., 2005)
Inoculate biochar with microorganisms before adding as soil amendment. Further
research on alternate ways to apply microbes with biochar will likely improve
microoganism affect in adding plant growth.
Use different laboratory soil tests to determine total metals instead of only recoverable
metals allowing better determination of adsorption effects/ immobilization of Pb by
biochar. Total metals analysis can be preformed using EPA method 200.8. Total metal
analysis is rarely performed because it requires tedious and extremely hazardous sample
preparation to completely dissolve all soil minerals and has increased monetary costs.
Two accepted procedures are heating the sample with a mixture of HF and HNO3 or
fusion (high temperature heating) with lithium metaborate. Both produce fairly toxic
solutions containing the dissolved metals. Total metals analysis will help answer
questions related to how the biochar is affecting the Pb within the soils.
Additional testing: Test soils for pH more widely using a pH probe. In order to best
understand how biochar is reacting within the soils more tests need to be done to
understand soil composition. Metal speciation tests are ideal but very costly. Weigh soils
before and after if possible and test for soil porosity before and after application of
biochar.
Overall larger sample sizes needed.
Additional Experiments
Biochar and Mustards
Results indicated that Pb was significantly affected by the soil amended with
biochar and microorganisms in combination with the biochar. Thus, a feasibility study
focused primarily on the affects of biochar is needed. In order to provide a more in depth
55
understanding, a more rigorous sampling procedure will be used and the test area will be
set up in one or two large plots with embedded subplots treated with slightly different
amounts of the biochar. The plots could consist of 12 meters of contaminated soils, tilled.
Then it will be subdivided into control areas of 1 square meter with no biochar added
interdispersed with plot areas with the biochar added as it was in this prior feasibility
study. This would allow better comparison of the soils that were only tilled and those
with the biochar and mustards grown in them illuminating the affects of only tilling
compared with the affects of tilling and adding biochar. As an alternative, the plots study
area could be set up with one side of the 12 square meters being the control and the other
side being treated with the biochar. Then the sampling would be done with random
sampling from each side with 6 samples from each made up of composite samples (i.e.:
taking 3 samples and mixing them together to form one composite homogeneous sample
and repeating this 6 times for each side).
Prior to tilling or adding biochar rigorous sampling should be done with an XRF
Niton Analyzer to accomplish a large sample size as the base range of contamination.
This can be done by removing the topsoil every 6 inches in a grid pattern to create a base
map. Then, there should be a round of three samples taken after tilling and then samples
taken in control plots and soil amended plots right after the addition and after plant
harvest. For this research, it is vital that the CEC and AEC be tested before and after
treatment. This can be done by air drying s grams of the soil samples and sending them to
a lab with an Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES)
machine in order to count the exchangeable cations and anions.
It may be that the biochar is merely adding biomass to the plots thus reducing the
overall concentrations of arsenic and lead. However, if this were the case the arsenic
concentration would decrease significantly as well. By conducting a more in depth
biochar analysis, these questions will be more clearly answered.
One issue that should be noted when leaving large tracts of contaminated soils
open to the air is the possibility of wind taking the contamination into unwanted areas as
well as increasing the likelihood of personal contamination through inhalation by
researchers. Also, in order to harvest and test after the tilling has occurred there will be
definite contamination of boots and clothing used in the field. This is a serious issue and
56
illustrates why separate plots were used in the initial feasibility study. Perhaps plastic
bags can be worn around the boots and then the contaminated soils can then be washed
off back into the soils after use.
Testing the Effects of Tilling
It would also be interesting and illuminating to conduct research aimed at the
affects of tilling and sampling to better understand how As and Pb varies in concentration
within the soil. This experiment would also include rigorous sampling. The area being
remediated would first be cleared of just the sod layer. Then an XRF Niton Analyzer
would be used to map out the surface soil contamination taking readings at every 6 inches
across the area. The area would then be subdivided into smaller sampling plots each 1 m
squared. From these plots soil samples will be taken in the same fashion as in the
feasibility study with 3 samples mixed together at 2 inches and three mixed together at 6
inches to create two samples from each plot for the initial samples. Then the area would
be tilled. Every 3 weeks samples will be taken over a one year period. Once at the end of
each season, the area will be mapped by the Niton XRF Analyzer. The initial map will be
created at the end of Winter and the final map will be created at the end of Fall while two
maps will be done in between, one at the end of Spring and one at the end of Summer.
Conduct ex situ experiments
Create a small laboratory style test by digging soil up and putting it in a deep
plastic tub on site. Apply the same amendments and soil testing protocol as in situ. This
will allow a better idea of how well the amendments are working at the site without the
uncontrolled movement of soils by ―soil engineers‖. This can help researchers form a
better projection of the length of time needed and how much of the soil is being affected
by soil movement in and out of the area.
Selection of alternative Species
Note on Pteris vittata
The ladder fern Pteris vittata was the original choice as the phytoremediation
hyperaccumulator for this research. However, upon further investigation not only was the
57
plant rather expensive at $5 (with little time to invest in growing and pollinating to grow
our own), the plant was a potential invasive species for the Pacific Northwest region. It
was listed on the Florida Invasive plant list by the Florida Exotic Pest Plant Council in
1999 and remains there today (FEPPC, 2009). Also, there is little evidence that it would
accumulate Pb as well.
Through a conversation with Norm Peck, a state employee with the Washington
State Department of Ecology, information was found on a 2-year study done on Vashon
Island using the ferns and found they did not accumulate Pb . They are hard to grow in
this climate because they need full sun for ½-2/3rds of the day and do not last well
through the winter causing less As to be accumulated the following year (Department of
Ecology website, 2005). He also expressed concerns over the ferns being a hazardous
waste after harvest. They need water during the growing season and Washington‘s sunny
growing season is usually dry.
A common concern is what to do with the plants after they have been harvested.
The argument is often answered by the idea that plants are lighter to transport than soil.
Also, there is a numerous amount of research on extracting the contaminants from the
plants for use in laboratories/and other chemical uses. One issue the fern research
illustrates is the difficulty of determining whether or not the soil is being remediated due
to soil variability. ―The young ferns planted in April through June this year contained less
than 1 part per million (ppm) As in their fronds at the time of planting. At season‘s end,
the As concentration in the fronds ranged from 828 to 16,000 ppm (dry weight) (Chinese
Brake Ferns, 2005). Even though the plants accumulated mass amounts of As the test
plots did not show a corresponding decrease.
In some plots, arsenic concentrations appear to have increased. However,
this is likely due to the high variability of arsenic in soil as shown in our
past Tacoma Smelter Plume studies. This variability makes determining
soil removal rates difficult, especially over only one year and two sample
sets (baseline and harvest in 2005). Mass balance calculations indicate a
slight reduction, though less than predicted. We cannot point to a
definable reduction in soil arsenic concentration in the test plots this year.
(Chinese Brake Ferns, 2005).
58
Grass
Using grass as a phytoaccumulator provides both phytostabilization and
hyperaccuualtion. The grass Agrostis tenuis is known for its ability to be tolerant in Cu
waste contaminated soils (Salt et al., 1995). Agrostis castellanai, Colonial bentgrass has
been shown to accumulate As and Pb (LID Technical Guidance Manual). These grasses
may have less biomass and take a longer period to remediate, but allows for easy harvest
through mowing and collection in a lawn mower bag.
Mycoremediation
A reassessment of the site for mycoremediation would be beneficial. Mycorrhizal
fungi have been coevolving with over 95% of the plants on earth through a symbiotic
association, exchanging important nutrients. Mustard plants happen to be in the 5% of
plants that do not form relationships with fungus (mycorrhizae.com). Thus, no fruiting
mushrooms or mycorrhizael mushrooms were used for this part of the study. Mentioned
before, mycoremediation was originally a part of the design for the feasibility study and
will possibly be applied after the second round of mustards are harvested depending on
whether the mustards accumulate or not. If the mustards hyperaccumulate As and Pb
mushrooms might hinder this process. However, if they do not hyperaccumulate arsenic
or lead mushrooms in combination with another plant such as a native fern, might make a
better guild.
Fungus has been shown to actively accumulate heavy metals out of soils. ―Fungi
in particular may be able to accumulate…metal(loid)s into their cells. The intracellular
uptake of metal ions from a substrate into living cells, known as bioaccumulation, may
lead to the biological removal of metals by fungi (Adeyemi, 2009)‖. Adeyemi
demonstrated the importance of fungus in the detoxification of arsenic by rendering the
arsenic in the soil from a soluble to an insoluble form. Two mushrooms are known to
hyperaccumulate As: Shaggy Mane and Shaggy Parisol (Macrolepiota rhacodes). Shaggy
parisol also accumulates Pb (Stamets, 2005). Both of these mushrooms have fruiting
bodies which occupy the very top layers of the soils. Thus, it would be difficult for them
to access deeper toxins within the soil. This issue might be addressed by a good
plant/mushroom combination where the plant will bring the metals toward the surface
59
with its root systems. Shaggy parasol is native to the Puget Sound area and is commonly
found in polluted soils, hard ground, grassy areas, and trails. This mushroom is able to
grow in a range of temperatures in the environment and grows from late fall to early
winter (Stamets, 2005).
A great deal of research has been done on the relationships between mycorrhizae
and biochar where the char has been used with great success as a carrier substrate for
arbuscular mycorrhizal fungi (Ogawa, 1994). The mycorrhiza obtain carbohydrates from
the plant and in exchange help the plant get access to more nutrients from the extensive
coverage of mycelium in the soil. Mycorrhiza can also transform phosphate to plant
available forms (Brundrett, 2003) and help reduce infection by pathogenic fungi
(Matsubara et al., 2002). Mycorrhizae abundance increases with biochar additions
(Warnock, 2000). This increase could be from reduced competition from saprophytes or
protection from grazers in micropores (Saito, 1989). However, using microorganisms
with the mycorrhizae may create unwanted complications between the two resulting in
competition for survival. A study using only biochar and mycorrhizae may have
interesting and significant results.
60
Afterward: Knowledge and Application
Eden reframed is a community ecoart project located on Vashon Island that
creates awareness about remediation and permaculture. Working with Beverly Naidus,
the Home Remedy Project gained attention through work done at the Eden Reframed site.
There, we created deep plant beds that allowed for water retention. We planted one side
of the garden with edible local plants and the opposite side with plants that were known
local remediators. Signs at the site provide information about heavy metal contamination
as well as information on other plants that remediate for fecal coliform or high methane,
even for depression. Working on Eden Reframed during the Home Remedy Project
allowed a more free expression of the heavy metal issue that brought people to a better
understanding of the issue in a safe and open environment.
The heavy metal contamination is only a small part of the overall destruction that
has occurred through industrialization. Being able to grow food locally in healthy soil is
vital and being threatened globally. Luckily, bioremediation is showing more positive
results when dealing with pesticides and petroleum pollution (Geetha and Fulekar, 2008;
Gavrilescu 2005; Seech et al. 2008) and there must is still be a way to remediate for As
and Pb using sustainable solutions.
There is a large gap between bioremediation research, the knowledge it has
generated and the application of this knowledge to the clean up of soils in the real world.
Billions of dollars have been provided to aid in the ―cleanup‖ of As and Pb but still has
not provided for every area contaminated especially privately owned land. ―‘Today‘s
landmark enforcement settlement will provide almost one billion dollars to clean up
polluted Superfund sites," said Cynthia Giles, Assistant Administrator for the EPA‘s
Office of Enforcement and Compliance Assurance (December of 2009). "This will mean
cleaner land, water and air for communities across the country.‘(EPA Compliance)‖ It is
distressing to see that after 30 years of the ASARCO smelting plant being closed the
61
people of Vashon and Maury Island are still being left to deal with the contamination on
their own without seeing many of the benefits from this funding.
Even though there are established positive results for phytoremediation on metal
extraction, it does not appear that this knowledge is being applied. One reason for this is
the difference between in situ remediation and research done in a controlled,
lab/greenhouse environment. Currently, the remediation work being done by The
Washington Department of Ecology involves digging and transporting the contaminated
soils to landfills which does not truly ―clean‖ the contamination, but just moves it to
another location.
Going deeper in order to find out why bioremediation of heavy metals was not
occurring, Illya Raskin was called because he owns a patent on specific B. juncea species
that are proven to remediate for As and Pb Never hearing back from him as to why the
remediation with B. juncea was not at all common a paragraph was finally found in the
book Trace Elements in Soils, the 2011 edition edited by Hooda. The patent was licensed
to Phytotech, Inc. who conducted the field research. Results concluded that the plants
were able to hyperaccumulate Pb at a high rate in nutrient hydrolic water, but not in soils.
In response to this, chelating agents were added to the fields, which induced the
extraction of the Pb by the Brassica juncea. However, further research showed that the
result of adding chelating agents caused Pb to leach into groundwater in high
concentrations.
Hooda et al. explains, ―It is very unfortunate that many researchers were misled
by these studies to believe that Pb Phytoextraction might be practical. Literally hundreds
of papers have since been published on Pb Phytoextraction with different plant species
and different chelating agents. None have demonstrated a cost-effective and
environmentally acceptable Phytoextraction technology for soil Pb. (p330)‖
With that said, biochar still could be a possible solution to the issue of Pb leaching
into groundwater during the remediation process and further research should go into
finding the right combinations in order to bioremediate Pb safely or contain it safely on
site in order to grow food in a safe environment. With the 30 years that the ASARCO
smelting plant has been closed, if bioremediation techniques had been implemented right
away using the right grass and the Pteris vittata ferns, it is possible the plants would have
62
taken much of the contamination out of the soils. The need for a process that is fast and
monetarily beneficial to involved parties has left Puget Sound with a very expensive
mess. Biormediation is a way to remediate this issue for good, but most methods are very
slow and require decades to be completed. This study highlights the difficulties of
conducting bioremediation for As and Pb on Vashon Island and suggests the importance
of more research in this area and ways it can be accomplished.
63
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―Comparison of mercury, lead and arsenic with respect to genotoxic effects on plant
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of Soil Science and Environmental Management. Vol 3(9), pp.241-249, 21
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hyperaccumulation in plants - Biodiversity prospecting for phytoremediation
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―Phytoremediation of Arsenic and Lead in Contaminated Soil Using Chinese Brake
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Chemistry and Physics, Western Carolina University,Cullowhee, NC 28723 From
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Academic Search Complete
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and Raskin, I. (1995). ―Phytoremediation: a novel strategy for the removal of
toxic metals from the environment using plants‖, Biotechnology 13: 468-475.
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San Juan, Charles (1994). Natural Background Soil Metals Concentrations in
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74
APPENDICES
Additional Information
USDA National Germplasm System
The mission of the National Plant Germplasm System (part of the Germplasm
Resource Information Network GRIN) of the USDA is to ―serve as the information
system for the documentation of plant, insect, animal and microbial germplasm
maintained by the U.S. National Genetic Resources program‖. Plant germplasm is
collected from around the world. Then curators and scientists preserve, evaluate, and
catalog this germplasm and distribute it to people with a valid use (Seeds for Our Future
1996). ―The National Plant Germplasm System is devoted to the free and unrestricted
exchange of germplasm with all nations and permits access to U.S. collections by any
person with a valid use (Seeds for Our Future 1996)‖ such as plant researchers and
breeders. However, there are some limitations. In order to maintain the collections they
only distribute 200 seeds of any particular variety to each individual request. When the
seeds were requested for this research only 200 of the 426308 B. juncea seeds could be
obtained. At least 1200 seeds are needed for this study. Although the cultivar 426308
found by Kumar et al. was the best known accumulator, another variety from a source
able to provide enough seeds was chosen. If the study was postponed a year the NPGS
seeds could be used as germplasm to provide the seeds for the research one year later.
I
Grant Proposals
April 30, 2010
The Harris and Frances Block Foundation
491 Ennis Hill Road
Marshfield, VT 05658
Dear Harris and Frances Block Foundation Board,
I am impressed by the breadth of efforts to which you have lent support, encompassing
such areas as forest preservation, food security, anti-nuclear and anti-genetic engineering,
education on peace and justice and on militarism, community composting, revitalization
of traditional ecological cultures, outreach and education for at-risk teenagers, and
independent media, and more. Your foundation is contributing greatly to overcoming a
wide range of social and environmental problems by supporting the work of these vital
grassroots efforts—for which funding is unfortunately not easy to come by in today‘s
world, and is therefore absolutely crucial. The values of environmental stewardship,
social justice and responsibility you express through this kind of support are very much in
alignment with the values we hold at SEEDS, and I greatly appreciate the opportunity to
collaborate with you.
Bob Spivey
Founder and Board President
Social Ecology Education and Demonstration School (SEEDS)
II
Harris and Frances Block Foundation
Grant Application
Cover Sheet
1. Organization name: Social Ecology Education & Demonstration School (SEEDS)
Date: April 28, 2010
2. Address: __PO Box 13126________________
_ Burton, WA 98013______________________
3. Contact Person & Title: Bob Spivey, President
Phone #___206-949-4786_____________
Email ___bobespivey@gmail.com_____
4. Person responsible for the program:__Jenn Coe_________
Phone # ___206-384-0973____________
Email
___Jenntree@gmail.com_______
5. Project Title: ____SEEDS Bioremediation Home Remedy Program_____
6. Estimated project start date: __June 2010___________
7. Amount requested: _______$6,535_____________
8. Project summary:
The SEEDS Bioremediation Home Remedy Program aims to demonstrate the
effectiveness of low technology phyto- and myco-remediation techniques in soil
contaminated by arsenic and lead on Vashon Island to levels below the stringent
standards set by Washington State. The program will demonstrate an accessible,
replicable model for remediating a soil condition of great concern not only to those living
on Vashon, but to many areas throughout the Puget Sound. The research plots will serve
as a hands-on practicum site for education on remediation approaches, as well as
permaculture and other approaches that embody grassroots, community-controlled
approaches to sustainability. The project for which we are currently seeking funds is the
first phase of a project that will provide ongoing training in remediation and restoration
throughout the area with particular focus on low-income communities.
III
Bioremediation Home Remedy Program
SEEDS Bioremediation Home Remedy Program
History and Mission of the Social Ecology Education & Demonstration School
Headquartered on Vashon Island in Washington State, the Social Ecology
Education and Demonstration School (SEEDS) helps meet the urgent need for an
educational ecological project aimed at both local and global communities. The mission
of SEEDS is to develop and offer educational experiences that enhance people‘s abilities
to knowledgeably and creatively address the interwoven social and ecological crisis of
our time. Through an intensive and interdisciplinary study, participants gain a critical and
comprehensive understanding of social and ecological reconstruction. SEEDS provides
participants with opportunities to test various reconstructive strategies by means of
individually designed practicum learning experiences.
Beginning last year, SEEDS has played a key role in the development of what has
come to be known as the ―Vision for Vashon.‖ A comprehensive community
development effort, Vision for Vashon sparked citizen work groups in affordable
housing, community health, community solar energy, alternative currency systems, food
security, and grassroots sustainability projects. The food security/food sovereignty group
has become a particularly active and robust group, and SEEDS‘ goals in relation to food
sovereignty include the promotion of collaborative farming/gardening, and education in
permaculture approaches.
Problem: Heavy Metals and Bioremediation
Soil remediation is a necessity for the Vashon community in order to enable
reliable, healthy and local food sourcing, an imperative especially for our Island
community. One particular challenge we face is the widespread contamination of soils
with heavy metals from the ASARCO smelting plant, operated from 1887 to 1986 in
Ruston, Tacoma, Washington (Glass, 2003), across the water from Vashon Island. The
southern half of the island was under the smelter plume windfall area, leaving it
contaminated with mass amounts of the heavy metals arsenic and lead. The EPA has
designated the ASARCO site a Superfund site since 1979 and has documented the
contamination of lead and arsenic in the adjacent areas. The Washington State
Department of Ecology (WSDOE) found concentrations of 360 parts per million (ppm) of
arsenic and 1300 ppm of lead on certain soils on the south side of Vashon Island. This
level of contamination is well over the EPA safe limit for bare soils and is more than
three times the limit for areas with children. It is far above Washington State's limit of 20
ppm concentration standard for arsenic and the state's 250 ppm for lead (WSDOE).
SEEDS has designed a research-based educational project to discern and
implement a system for removing these contaminants using bioremediation methods. Our
priority is that the system be affordable, effective and replicable to other communities.
We will freely share our findings with other areas facing the challenge of contaminated
soils, and we anticipate that our research will benefit countless communities in their quest
of restoring land for food production and other community needs.
Bioremediation Home Remedy Program: Goals and Objectives
SEEDS envisions a permaculture ―make-over‖ of bioremediated garden spaces
that have been largely abandoned through concerns about contamination. The Home
Remedy Program aims to provide a proven, replicable, and affordable model for
IV
Bioremediation Home Remedy Program
remediating soils contaminated with the arsenic and lead. Bioremediation techniques are
inexpensive and holistic, providing healthy living systems for daily life and food
production.
Our goal for the Home Remedy Program is to demonstrate that contaminated soils
within the smelter plume area of Vashon can be remediated through ecological and
accessible low-technology means for safe food production, according to the rigorous
standards of Washington State, which are considerably more stringent than the EPA
standards. The objective of this particular study is to compare effectiveness between low
and high technological techniques using three different ecological methods: funguses,
micro-organisms and ferns. We will then further study these methods‘ effectiveness when
working together, to view their effectiveness in a ―guild.‖ A guild is a permaculture term
meaning ―harmonious assembly of species (Mollison, 60)‖.
These test sites will be transformed into sites for on-going community education
in both bioremediation and permaculture approaches, providing a positive and lasting
impact not only on the health of Vashon Island‘s 13,000 residents but on other
communities facing similar challenges. The program will also promote food sovereignty,
which means not merely food security (which might be obtained through food transported
long distances), but the maximizing and democratizing of local resources for food
production.
Study Design
The Bioremediation Home Remedy initial study will compare bioremediation
techniques using low technology (locally based and sustainable resources) with those
using higher technology techniques (imported and more expensive resources) within
contaminated soils on Vashon Island. By testing three techniques at a low and high
technological level, a better understanding will be gained at the local level of different
cost variables as well as the bare minimum needed to successfully bio-accumulate the
contaminants. The purpose of the two technological levels is to provide replicable
practices for people with varying funding resources, while maintaining scientific
accuracy. We hypothesize that there will be negligible differences between the low and
high technology methods of bioremediation. We also hypothesize that the guild
bioremediation plots will be more effective at remediating the soil than the individual
specie and species plots.
Methodology
SEEDS researchers will start with 18 one meter square plots, inoculated with
three different sets of organisms including one control plot. There will be two plots
inoculated with the fungal spawn of Shaggy mane (Coprinus comatus), two plots
inoculated with specific blends of microorganisms, and four plots planted with ferns. We
plan on comparing the local Lady fern (Athyrium filix-femina) with the non-native
Chinese brake fern (Pteris vittata) which has been studied for successful arsenic
remediation. There will be two plots with Lady ferns with Shaggy mane mushrooms, two
plots with Lady ferns and microorganisms, and two plots with microorganisms with
Shaggy mane mushrooms. The last plot for each set will be a guild of all three organisms.
Low technology methods and plots will consist of hand tilled plots, wild harvested
Shaggy mane mycelium to be cultivated, compost tea from local sources and wild
V
Bioremediation Home Remedy Program
harvested Lady ferns. The high technology plots will be comprised of purchased Shaggy
mane spawn, a specialty blend of BioKleen probiotics, and purchased Lady ferns. For the
high technological plots a mechanized tiller will be used.
The study will be conducted over an initial six month period to allow for a full
growing season to be completed. Also, as a part of the research process, a six month
education program happen, beginning in June and culminating with a public workshop
that highlights the bioremediation program within the framework of ―Radical
Sustainability,‖ a vision SEEDS has adopted from Scott Kellogg and Stacy Pettigrew of
the Rhizome Collective. Radical Sustainability champions the necessity that resources
required for meeting people‘s needs be designed, built, maintained, and controlled by
those who use them, and materials be likewise accessible, low-cost, and shared. The
SEEDS Home Remedy Program works toward this vision. The Home Remedy Program
will also feature an educational art exhibit dramatizing the processes and benefits of
bioremediation, designed by noted eco-artist Beverly Naidus.
Analysis
Testing will be done with a Thermo Scientific Niton® XRF analyzer to conduct
Positive Material Identification (PMI), with five percent of the samples sent to a King
County lab for verification, as dictated by the EPA. The analysis procedure will consist of
the following steps:
We will take nine samples from each plot for initial testing. Each sample will be
sieved and grinded down with mortar and pestle according to the EPA's
procedural guidelines. Then the nine processed samples from the same plot will
be mixed together and sub-sampled three times, repeating this for each plot's
group. The sub-samples will be compacted into a small testing container and
analyzed three times for an average. We will continue this soil analysis every
month for six months.
Shaggy mane mushrooms will be harvested after 3-4 months upon their fruiting.
Each mushroom from its specific site will be dehydrated and powdered, then
mixed with samples from its plot and sub-sampled three times. Each sub-sample
will be compacted into a small testing container and analyzed three times for an
average, with five percent of the samples sent to a King County lab. The same
procedure will be used for the Lady ferns from each plot.
The categorical data sets will be analyzed with a Chi-squared analysis to insure
statistical significance. Our categorical independent variables are each plot,
while our dependent variables will be the fruiting mushroom bodies, aerial
portions of the ferns and the control plot. The before and after levels of lead and
arsenic in each plot will then be compared to the control plots using T-tests
which is typically used to compare the before and after samples. In order to
observe the changes that occur over time, measurements taken each month will
be plotted on an x-y scatter plot to show changes in concentration.
We will compare the differences between low and high technology methods and
each method‘s ability to remediate the soil. The guild plots with all three sets of
organisms will be compared. Each plot will be examined by progression of
VI
Bioremediation Home Remedy Program
change over time and how it effected the remediation. Using a Pearson's test we
will analyze the correlation between the fruiting mushroom bodies and the soil
in which they grew. The same test will be done for the aerial portion of the
Lady fern and its soil. We will also conduct Analysis of Variance (ANOVA)
which compares three or more means in order to find the most efficient process.
Evaluation
The Bioremediation Home Remedy Program will be evaluated on three main
principles. The first criteria for evaluation will be the ability of the bioremediation
process to successfully clean the contaminated soils, confirmed by monthly testing of the
soil and aerial bodies of the fungi and Lady Ferns. The second component will be the
collection of scientific data to gain a better understanding of bioremediation processes
and interactions between species. This will give residents, as well as local, state and
federal agencies better tools for remediating contaminated soils. The last important
principle to be evaluated will be the level of community involvement and education. This
will be assessed by the attendance at three public workshops held by SEEDS at the
bioremediation sites and by the community‘s feedback and education about the study,
including articles in the local newspaper, outreach at the local farmer‘s market and other
venues, and updates on the SEEDS‘ website. Further evaluation will be done as the Home
Remedy Program is put into practice throughout the community.
Sustainability
The Bioremediation Home Remedy Program uses and addresses the three pillars
of sustainability: incorporating the importance of community education and
empowerment, providing economic support and resources, and keeping the ecological
environment a priority. SEEDS is funded by workshop tuition fees and a steady stream of
small and large private donations, organized partly through membership in our Rhizome
Club. SEEDS has also received several small grants and developed earned income
products and services. Volunteers and a pulsing Puget Sound community provide the
momentum for SEEDS to continue to promote educational experiences that make lasting
changes to better the global community.
VII
Bioremediation Home Remedy Program
SEEDS Bioremediation Home Remedy Program Budget
High Tech
On-site work
Mechanized tiller
Shovels (hand tilling)
Site Development (preparation)
Labor
Remediation organisms
Fungi Culture
BioKlean Culture
Chinese Brake Fern
Lady Fern harvest and
propagation
Homegrown Culture
Compost Tea
Other associated costs
Transportation
Lab testing
Education
Unforeseen Expenses
Low Tech
Total
$390.00
$75.00
Volunteers
$250.00
$2,100.00*
$155.00
$300.00
Donated
Volunteers
$390.00
$300.00
$75.00
$155.00
$250.00
$2,100.00
$310.00
$275.00
$275.00
$30.00
$80.00
$550.00
$30.00
$80.00
$250.00
$300.00
$350.00
$250.00
$250.00
$300.00
Donated
$500.00
$600.00
$350.00
$250.00
Total
$4,395.00
$1,390.00
$5,785.00
*Estimate from a supplier of probiotic microorganism blends, based on suggested dosage and
delivery costs.
VIII
Bioremediation Home Remedy Program
Bioremediation Home Remedy Program
IX
References Cited
Glass, Gregory L. Environmental Consultant (2003) TACOMA SMELTER PLUME
SITE CREDIBLE EVIDENCE REPORT: The ASARCO Tacoma Smelter and
Regional Soil Contamination in Puget Sound, FINAL REPORT September 2003.
Tacoma-Pierce County Health Department and Washington State Department of Ecology
[http://www.ecy.wa.gov/programs/tcp/sites/tacom_smelter/Sources/Credible_Evidence/w
eb%20pieces/Credfinl.pdfa]
Mollison, Bill (1988). PERMACULTURE: A Designers‘ Manual. Second Edition. Am
Tagari Publication, McPherson‘s Printing Group, Maryborough, Tasmania, Australia
Scott Kellogg and Stacy Pettigrew (2008). Toolbox for Sustainable City Living: A DoIt-Ourselves Guide. South End Press, Cambridge, MA http://radicalsustainability.org
SEEDS: http://www.socialecologyvashon.org/index.php
Washington State Department of Ecology (2002). Washington State Department of
Ecology Toxics Cleanup Program Tacoma Smelter Plume Site, King County
Mainland Soil Study Executive Summary, March 2002.
http://www.kingcounty.gov/healthservices/health/ehs/toxic/TacomaSmelterPlume/backgr
ound.aspx#timeline
Bioremediation Home Remedy Program
X
May 13, 2011
The Harris and Frances Block Foundation
491 Ennis Hill Road
Marshfield, VT 05658
Dear Harris and Frances Block Foundation Board,
Bob Spivey
Founder and Board President
Social Ecology Education and Demonstration School (SEEDS)
The SEEDS Bioremediation Home Remedy Program aims to demonstrate the
effectiveness of low technology phyto- and myco-remediation techniques in soil
contaminated by arsenic and lead on Vashon Island to levels below the stringent
standards set by Washington State. The program will demonstrate an accessible,
replicable model for remediating a soil condition of great concern not only to those living
on Vashon, but to many areas throughout the Puget Sound. The research plots will serve
as a hands-on practicum site for education on remediation approaches, as well as
permaculture and other approaches that embody grassroots, community-controlled
approaches to sustainability. The project will now be entering into the second year of the
first phase where it aims to provide ongoing training in remediation and restoration
throughout the area with particular focus on low-income communities.
Bioremediation Home Remedy Program Update
XI
SEEDS Bioremediation Home Remedy Program Update
History and Mission of the Social Ecology Education & Demonstration School
Headquartered on Vashon Island in Washington State, the Social Ecology
Education and Demonstration School (SEEDS) helps meet the urgent need for an
educational ecological project aimed at both local and global communities. The mission
of SEEDS is to develop and offer educational experiences that enhance people‘s abilities
to knowledgeably and creatively address the interwoven social and ecological crisis of
our time. Through an intensive and interdisciplinary study, participants gain a critical and
comprehensive understanding of social and ecological reconstruction. SEEDS provides
participants with opportunities to test various reconstructive strategies by means of
individually designed practicum learning experiences.
SEEDS has played a key role in the development of what has come to be known
as the ―Vision for Vashon.‖ A comprehensive community development effort, Vision for
Vashon sparked citizen work groups in affordable housing, community health,
community solar energy, alternative currency systems, food security, and grassroots
sustainability projects. The food security/food sovereignty group has become a
particularly active and robust group, and SEEDS‘ goals in relation to food sovereignty
include the promotion of collaborative farming/gardening, and education in permaculture
approaches.
Over the last year, the Home Remedy Project has promoted the development of a
working understanding of how to create healthy soils on Vashon allowing for the
progression of research in the area of bioremediation within the community. By bringing
experienced remediation specialists, such as Howard Sprouse from The Remediators to
consult on the project as well as supporting interested researchers in the improvement of
the initial Bioremediation Home Remedy design.
Over the winter we have researched, compiled resources, contacts, consultants and revamped our methods and
procedures for this project to get better results and provide a more effective model for our community.
Lessons Learned and the Initial Impact of the Project
The Home Remedy Program is still a blend of recent bioremediation science,
permaculture design principles and community driven needs. Over the past year our
research has furthered our understanding of what will work best for our communities
needs while keeping in line with scientific principles. This approach has taking time to
properly plan and implement. We have met only a small portion of the goals we set out to
meet in our proposal last year but intend to meet our goals this year. Implementing such
an elaborate experiment has proven more complicated than first considered. As more
research was conducted over the months of May and June of 2010, discoveries were
made such as the invasiveness of the ferns Pteris vittata, and how to properly inoculate
mushrooms outdoors. Due to timing and the need to conduct more in depth research, as
well as acquire all of the necessary equipment for the study, the desired timeline for
starting the main body of research has been delayed to this year in order to work with the
growing season.
Last fall 7 plots were started at our site on south Vashon Island as a short term
experiment to see the affects of homemade compost teas and professional grade teas. The
time frame of the experiment was only 8 weeks and did not produce any qualitative data
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that is of any statistical significance. The short time frame was due to a late start in early
October and the end of our summer /fall season in late November. This did, however,
give us insight into improving our sampling and inoculation methods. We experienced
some issues with using the XRF Analyzer due to its unavailability. We also had a very
cold and wet fall that did not bode well for our mustard greens.
With the return of the Niton XRF Analyzer to the Seattle area, we have been able to
locate the most contaminated locations for plot placement and, one year later, the project
is moving forward with sprouts in the ground and the baseline soil samples being
analyzed.
Accomplishments made within the program include a better understanding of the
complicated multi-specie guilds. An improved set of guild combinations have been
formulated that are more likely to perform and be ecosystem safe while still being
affordable. We have turned away from the more complicated low and high technology
comparisons toward a method that is low and high technologies combined in a medium
cost. Now we are using our plot space to assess the guild combinations rather than both
the factors of the guilds and the technology methods at the same time. This will give us
more emphases on the ability to remediate rather than the affordability. Also, all of the
necessary equipment has been purchased and prepared for research implementation.
More people are now aware of the research and are becoming involved.
Professors form the Evergreen State College are excited for the research and are
providing support through education and access to lab facilities through their Masters of
Environmental Studies student, Shannon Clay, who is writing her thesis on this
bioremediation project. Freidman and Bruye, a local Seattle Lab who are EPA approved
for soil testing have offered to do part of the soil testing pro bono to ensure readable
results of the study. Three presentations have been given on the issues around the
ASARCO plume pollution and the Bioremediation Home Remedy Programs efforts to
remediate these soils and to further educate the communities affected. These have
highlighted the questions that still remain within this newly developing field and
provided community connections in support of the work. Home Remedy has also been
highlighted in the SEEDS Spiral Visions Permaculture Soils Workshop weekend and in
Beverly Naidus‘s eco-art edible forest garden remediation instillation at a local skate
park. Undergraduate students are becoming involved in the process from both The
Evergreen State College and Seattle Central to help with biochar inoculation, soil and
plant testing, and the implementation of the project at the site.
The biggest lesson being learned through the Bioremediation Home Remedy
Program is that of patience as well as thoroughness of study design. Phytoremediation
has most often worked over long periods of time with the most successful remediation
being done after three years of the hyperaccumulators growing in the contaminated spots.
Our project aims to have a more efficient process by creating healthier soils for the plants
to grow in even in these stressed conditions. We must acknowledge that this is a new
field of study and most research has been conducted in labs rather than on site. We hope
to see strong results within the first year, but can not guarantee that will be the case. As in
all science, we are working within a hypothesis that can be limited in our human
understanding of the biological processes that take place within soils and root
communities. Also, it may take more time to actually but ideas into action especially
when working with different people over long distances. It has been helpful for SEEDS
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to keep making timelines and schedules to meet deadlines, but to recognize when it is
okay to allow plans to address the schedules life presents us with.
Sustainability
The Bioremediation Home Remedy Program uses and addresses the three pillars
of sustainability: incorporating the importance of community education and
empowerment, providing economic support and resources, and keeping the ecological
environment a priority. SEEDS is funded by workshop tuition fees and a steady stream of
small and large private donations such as Freidman and Bruye Inc.‘s offer to conduct soil
sampling for free. SEEDS has also received several small grants and developed earned
income products and services. Continued help from volunteers and a pulsing Puget Sound
community are providing the momentum for SEEDS to continue to promote educational
experiences that make lasting changes to better the global community.
Financial Statement
SEEDS Bioremediation Home
Remedy Program Budget Spent
Once we started working with
organizations to get the materials we needed, it
became less expensive than originally suggested.
However, monies were needed to fund consults
with remediation specialists and an increase in
Cost
On-site work
55 gallon rain barrels (3)
Drip Irrigation Equipment
Shovel
Pipe Cutter
Chicken Wire
Stakes and used wood material
Bags
String and sampling tools
Remediation organisms
Mycogrow soluble 12ounces
BioKlean Culture
Mustard Seeds
Other associated costs
Transportation
Donated Items
Mechanized tiller
Soil Testing
Biochar
Total
$165.00
$200.00
$25.00
$15.00
$65.00
$65.00
$6.00
$20.00
$74.00
$225.00
$6.00
$500.00
$1,346.00
SEEDS Bioremediation Home
Remedy Program Budget for
Future Spending
Cost
Remediation organisms
BioKlean Culture
Weed Whipper
Other associated costs
Plant Tissue Assessment
Transportation
$2,100.00
$500.00
Total
$3,189.00
$514.00
$75.00
travel costs also occurred.
Total Amount Projected $4,535.00
Extra Provided
$1,250.00
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The extra provided will likely be used toward education programming and
unforeseen costs.
Following is the current goals and objectives and the updated study methodology
and the evaluation components.
Bioremediation Home Remedy Program: Goals and Objectives
SEEDS envisions a permaculture ―make-over‖ of bioremediated garden spaces
that have been largely abandoned through concerns about contamination. The Home
Remedy Program aims to provide a proven, replicable, and affordable model for
remediating soils contaminated with arsenic and lead. Bioremediation techniques are
inexpensive and holistic, providing healthy living systems for daily life and food
production.
Our goal for the Home Remedy Program continues to be to demonstrate that
contaminated soils within the smelter plume area of Vashon can be remediated through
ecological and accessible low-technology means in order to provide safe food production,
according to the rigorous standards of Washington State, which are considerably more
stringent than the EPA standards. The objectives of this particular study have evolved to
be ecologically sound as well as obtainable goals for an initial study of this size. Now the
objective is to compare effectiveness between three combinations of different ecological
methods: funguses, micro-organisms and mustard plants, rather than ferns. The The
different combinations will allow us to study these methods‘ effectiveness when working
together, to view their effectiveness in a ―guild.‖ A guild is a permaculture term meaning
―harmonious assembly of species (Mollison, 60)‖.
These test sites will be transformed into sites for on-going community education
in both bioremediation and permaculture approaches, providing a positive and lasting
impact not only on the health of Vashon Island‘s 13,000 residents but on other
communities facing similar challenges. The program will also promote food sovereignty,
which means not merely food security (which might be obtained through food transported
long distances), but the maximizing and democratizing of local resources for food
production.
Study Design
The Bioremediation Home Remedy initial study has evolved since the grant
proposal was funded. After the proposal was sent to the Harris and Frances Block
Foundation, more research revealed the invasiveness of the fern species chosen to use for
the phytoremediation component. Another plant, Brown Mustard (Brassicaea juncea),
has been revealed as a well known hyperaccumulator of both arsenic and lead. The initial
study has also been simplified to only test different guilds rather than one species at a
time. If one of the guilds is successful, then further research will look at the plants,
microorganisms, and fungus separately to see if only one of the components is needed for
a successful remediation. We hypothesized that there would be negligible differences
between the low and high technology methods of bioremediation, and thus combined the
methods for a doable, affordable, simplified research design. We also hypothesized that
the guild bioremediation plots would be more effective at remediating the soil than the
individual specie and species plots. Therefore, by studying the guilds first we can more
easily afford soil testing in the initial stages of the research as we build more partnerships
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that will enable further funding of the project at a more complex level of research. The
guilds are all focused toward phytoremediation, the process of plant accumulation of
toxins, aiding in the acceleration and efficiency of this process.
Methodology
Due to the changes made to the study design the methods have changed as well.
SEEDS researchers will now start with 16 one meter square plots (rather than 18) and 2
control plots (instead of 1). Instead of using specific mushrooms such as Shaggy mane
which requires close monitoring when fruiting bodies emerge, an all around mycelium
will be applied for inoculating the soils. We will use mustard seed (Brassicacea juncea)
which has been studied for successful arsenic and lead remediation. Biochar is a new
addition to the research design and will be used to house mycelium and microorganisms.
Each plot will have one of four combinations with the overall all goal of an efficient and
affective phytoremediaiton. Four plots will have a guild of brown mustard (Brassicaea
juncea), mycelium to increase plant uptake, and a blend of microorganisms called
BioKlean. Four plots will have mustard seed, mycelium, and biochar. Another four plots
will have mustard seed, BioKlean and biochar. The last four plots will have mustard seed,
mycelium, BioKlean, and biochar. Low technology methods will be used as each plot
will be hand tilled and hand seeded while the high technology methods will be kept using
a specialty blend of BioKleen probiotics, a drip irrigation system, and purchased
mycelium.
The study will be conducted over an initial six month period starting May 12th,
2011to allow for a full growing season to be completed. Also, as a part of the research
process, various education programs are happening. One permaculture hands on lesson
occurred May 8th during a soils workshop that focused on remediation using these
methods. Other workshops will bring hands on education to the site. One researcher is
conducting her thesis work at the site while other SEEDS researchers are gaining wisdom
in different approaches as well. By the fall a culminating public workshop will take place
that highlights the bioremediation program within the framework of ―Radical
Sustainability,‖ a vision SEEDS has adopted from Scott Kellogg and Stacy Pettigrew of
the Rhizome Collective. Radical Sustainability champions the necessity that resources
required for meeting people‘s needs be designed, built, maintained, and controlled by
those who use them, and materials be likewise accessible, low-cost, and shared. The
SEEDS Home Remedy Program works toward this vision. The Home Remedy Program
is also featured in an educational art exhibit at a local skate, frisbee and bike park
dramatizing the processes and benefits of bioremediation, designed by noted eco-artist
Beverly Naidus.
Analysis
Initial testing has been done with a Thermo Scientific Niton® XRF analyzer to
conduct Positive Material Identification (PMI) on site to locate where the most
contamination occurs within the sites. 36 initial soil samples are being analyzed by
Friedman & Bruya, Inc. Environmental Chemists for arsenic and lead levels testing on a
Inductively Coupled Plasma Mass Spectrometer (ICP-MS) with a concluding sample set
to be tested in the late fall. Plant tissue will also be tested twice for arsenic and lead, once
for each plant harvest. The analysis procedure will consist of the following steps:
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We will take six sub-samples from each plot for initial testing with three taken
randomly at 2inches and three taken at 6 inches deep. Each sample will be
sieved and grinded down with mortar and pestle according to the EPA's
procedural guidelines. Then the three will be from the same plot and depth will
be mixed together and sub-sampled three times, repeating this for each plot's
group. The sub-samples will be compacted into a small testing container and
analyzed three times for an average. We will conduct this soil analysis at the
beginning and end of the six months. One set of plots will be analyzed each
month.
Brassicaea juncea will be harvested after 60 days before the plant goes to seed.
One plot from each set will leave the plants to seed. Each plant from its specific
site will be dehydrated and powdered, then mixed with samples from its plot
and sub-sampled three times. Each sub-sample will be compacted into a small
testing container and analyzed three times for an average with the Niton XRF,
with five percent of the samples sent to Friedman and Bruya, Inc.
The categorical data sets will be analyzed with a Chi-squared analysis to insure
statistical significance. Our categorical independent variables are each plot,
while our dependent variables will be the fruiting mushroom bodies, aerial
portions of the ferns and the control plot. The before and after levels of lead and
arsenic in each plot will then be compared to the control plots using T-tests
which is typically used to compare the before and after samples. In order to
observe the changes that occur over time, measurements taken each month will
be plotted on an x-y scatter plot to show changes in concentration.
We will conduct Analysis of Variance (ANOVA) which compares three or
more means in order to find the most efficient process.
Evaluation
The Bioremediation Home Remedy Program will be evaluated on three main
principles.
The first criteria for evaluation will be the ability of the bioremediation process to
successfully clean the contaminated soils, confirmed by testing of the soil and aerial
bodies of the mustard plants. We are just now (May 11th, 2011) planting our first round of
plants and sending off our first samples. More time is necessary to see whether this
process is successful.
The second component will be the collection of scientific and social data to gain a better
understanding of bioremediation processes and interactions between species. This will
give residents, as well as local, state and federal agencies better tools for remediating
contaminated soils. We have come a long way in our understanding of Bioremediation
and are successfully sharing it with different groups through workshops and
conversations at a more personal level. Data has been collected and more is on the way!
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The last important principle to be evaluated will be the level of community involvement
and education. This will be assessed by the attendance at three public workshops held by
SEEDS at the bioremediation sites and by the community‘s feedback and education about
the study, including articles in the local newspaper, outreach at the local farmer‘s market
and other venues, and updates on the SEEDS‘ website. We plan to have bigger events
focused toward this project in particular and have held smaller gatherings with Home
Remedy as one of the main topics. Further evaluation will be done as the Home Remedy
Program is put into practice throughout the community.
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The Evergreen State College Student Activities Fund
Project Description and Timeline
Background
History and Mission of SEEDS
Headquartered on Vashon Island, the Social Ecology Education and
Demonstration School (SEEDS) works to meet the urgent need for an educational
ecological project aimed at both local and global communities. The mission of SEEDS is
to develop and offer educational experiences that enhance people‘s abilities to
knowledgeably and creatively address the interwoven social and ecological crisis of our
time. Through an intensive and interdisciplinary study, participants gain a critical and
comprehensive understanding of social and ecological reconstruction. SEEDS provides
participants with opportunities to test various environmental reconstructive strategies by
means of individually designed practicum learning experiences.
Beginning last year, SEEDS has played a key role in the development of ―Vision
for Vashon.‖ A comprehensive community development effort, Vision for Vashon
sparked citizen work groups in food security and grassroots sustainability projects.
SEEDS‘ goals in relation to food sovereignty include the promotion of collaborative
farming/gardening, and education in permaculture approaches. Through SEEDS the
following research project is being proposed as a permaculture bioremediation process to
alleviate heavy metals in soils.
Heavy Metals on Vashon
Smelting plants have caused long lasting impacts on surrounding environments.
Even after smelting plant closings, heavy metals are left behind in soils causing
contamination and toxicity. Vashon and Maury Islands of the South Salish Sea presently
have high levels of arsenic and lead in the soils due to the American Smelting And
Refining Company (ASARCO) smelting plant, operated from 1887 to 1986 in Ruston of
Tacoma, Washington (Glass, 2003). The southern half of Vashon Island and all of Maury
Island were under the smelter plume windfall area, leaving the areas contaminated with
large amounts of the heavy metals, arsenic and lead. These metals impact the residents‘
ability to grow food for personal and market consumption due to the detrimental impact
they have on human health when inhaled or absorbed through the skin. Soil remediation
is a necessity for the Vashon community in order to enable reliable, healthy and local
food sourcing.
While the ASARCO plant was designated a Superfund site in 1983 by the EPA.
Under Superfund regulations the EPA has documented the contamination of lead and
arsenic in the adjacent areas (EPA, 2009). The Washington State Department of Ecology
(WSDOE) found concentrations of 460 parts per million (ppm) of arsenic and 1300 ppm
of lead on certain soils on the south side of Vashon Island (Glass, 2003). This level of
contamination is well over the safe limit for bare soils and is more than three times the
limit for areas with children (Glass, 2003). These levels are far above Washington State's
limit of 20 ppm concentration standard for arsenic and the state's 250 ppm for lead
(WSDOE). See Table 1.
Soils contaminated with heavy metals such as lead and arsenic can be dangerous
to humans and may be ingested, inhaled or absorbed through the skin. Simply being
outside and tracking the contaminated soil into the house on shoes and clothes is a means
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The Evergreen State College Student Activities Fund
of ingestion. Growing vegetables in home gardens is also a way in which heavy metals
enter the body (Department of Ecology State of Washington, 2010). Excessive exposure
to arsenic can cause lung, bladder and other cancers to humans (Stamets, 2005). Lead
exposure affects bones, reproductive and nervous systems and has been shown to be
detrimental to the developing human brain.
Bioremediation
Bioremediation is the decontamination method used on sites utilizing organisms,
namely plants, fungi, and microorganisms. There are several advantages to
bioremediation methods versus other forms of remediation. Bioremediation actually
transforms the contamination, such as lead or arsenic, and even radionuclides such as
uranium compounds, present in the soil into something that is less toxic (Iwamoto and
Nasu, 2001). More traditional methods of remediation simply remove the contaminated
soil and deposit it in another location, and does not address the toxicity leaving it for
future generations. Bioremediation practices also tend to be low cost, when compared to
other methods for remediation (Lloyd and Renshaw, 2005). Another advantage for
bioremediation is the multiple organisms that can be used for bioremediation, each with
their own strengths.
In our study, we will be using compost tea and a microbrial cocktail called
BioKlean, mycorrhizae and Shaggy Parasol for the fungi reassimilation and accumulation
of arsenic and lead, and mustard plants for hyperaccumulation. We will be looking at low
and high cost methods. All of the research will be done in back yards of Vashon
Residents and in Public Parks.
The Evergreen Component
The Evergreen component of the SEEDS Bioremediation Home Remedy Program
will provide a pivotal piece to the overall goal of the project by having current
undergraduate students in the Environmental Analysis class help me conduct soil
sampling on Vashon Island and soil testing for arsenic and lead on the Inductively
Coupled Plasma Mass Spectrometer (ICP-MS) at the Evergreen Campus this spring
quarter. Then we will able to set up a statistical baseline of contamination levels for the
concurrent readings to be compared with. The project will include a soil collecting field
trip in early April (or possibly even late march) to Vashon where samples will be
collected from each test plot. On Vashon, they will be shown various projects being
implemented by SEEDS while we have open discussions about various social ecology
issues occurring within the community. After the soil samples are taken, analysis on the
samples will be done the following weeks in April. Then the results will be mapped and
statistically analyzed (in order to find variance) to be presented in the EA class in June as
the quarter‘s final presentation. The students will also get the opportunity to participate in
a permaculture class being held at the site on May 8th for the Soil Education Day in the
Spiral Visions Social Ecology Education and Demonstration School (SEEDS)
Permaculture Design Course. The overall Bioremediation Home Remedy Project will be
concluded in one to two years from now when the site will be evolved into a
permaculture food garden. The funding request being asked for the Student Foundation
Activity Grants is for the soil testing and soil sampling trip only.
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The Evergreen State College Student Activities Fund
Product
There will be many end products to the Bioremediation Home Remedy Project, but
specific to the Evergreen component of the project students will be provided with the
opportunity to gain field and lab experience working on a project that benefits the larger
community. They will be contributing to my thesis work, important remediation research,
as well as community health and awareness. Products will include learning experience,
documented scientific analysis of these contaminated soils, and a thesis paper. A baseline
reading of the levels of arsenic and lead in the soils at this site is vital in understanding
the viability of the different remediation techniques being studied. Student‘s will be able
to continue their participation in this research and become involved at many levels in the
1-3 year process of turning a polluted, hazardous site into a permaculture garden.
Current Academic Work
I am currently a student in Evergreen‘s Masters of Environmental Studies (MES)
Program beginning work on my thesis. I have been working with SEEDS in contracts and
through volunteer work for the past year in order to fund and implement the
Bioremediation Home Remedy Project. I have done extensive research, alongside
Evergreen students LaDena Stamets and Austin Walsworth, on some of the most efficient
remediation techniques dealing with heavy metals. The proposed project as outlined in
the background section of this request, will be focused on using different microbrial
cultures, fungal, and plant based remediation in combinations and alone in high and low
technology plots. I have been contracting with SEEDS to do research in the arts, social
ecology, and various food system ideas.
Importance to My Evergreen Career
Receiving funding for the soil sampling and testing while providing students with
scientific and community building experiences will greatly impact the ability of my thesis
work to be conducted. The cost of having a science lab do the testing is very expensive,
around $18,000, and does not bring this opportunity to science students who have been
working in the EA class. Receiving funding for the soil testing is pivotal, but providing
hands on experience for students is an extra benefit for all involved.
In line with Evergreen’s Teaching and Learning Values
This is an interdisciplinary study enabling scientific procedures to overlap and
commingle with real world problems working towards real world solutions. Bringing
students into this process using their scientific skills on the ICP-MS in relation to
remediation and permaculture practices allows these skills to be involved in contributing
to the mitigation of the toxicity of heavy metals in people‘s homes and back yards. This
is also a collaborative process bringing many students together to focus on one issue
where they can share their experiences, skills and knowledge. This project also allows the
students to practice their own beliefs and judgments on the best ways to deal with
situations inside and outside of the lab in relation to the bioremediation research and,
mainly, the intricacies of soil testing. By having these students participate in my research,
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The Evergreen State College Student Activities Fund
they will help me to apply abstract theories in my project and will allow me the benefit to
participate in the real testing of the soils.
Significance
Funding the testing of these soils is significant in my personal research and in the
research of the remediation community at large. Furthermore, it will significantly impact
those students who are able to participate in the specifics of the soil testing bringing them
into a bigger focus of what those soils are a part of; a community working to grow their
own food, the EPA trying to find viably and cost effective methods to deal with the
damage left from the industrial revolution, and the Evergreen community being able to
support this process. I am ready to get dirty and implement my thesis design and methods
with some real hands on work!
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The Evergreen State College Student Activities Fund
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Clay_SMES2012.pdf