TAG reports: Volume 2, Number 2;
June, 1993
009 Superfund Site: Altama Schoolyard Testing and Review of the Record of Decision
Overview
This issue of the newsletter presents two separate aspects of TAG grant activities at the
009 Superfund Landfill. The first part is a discussion of toxaphene testing at the Altama
Elementary playground. Also in this newsletter is an examination of the Record of Decision
for in situ stabilization of the landfill. More specifically, the decision to perform an
on site study of the usefulness of stabilization at the dumpsite.
Testing of The Altama Elementary School Playground
Toxaphene is the primary "contaminant of concern" at the 009 Superfund site
adjacent to the Altama Elementary school. During earlier studies this chemical, a banned
pesticide, was found in the drainage ditch running from the dumpsite through the
schoolgrounds. In recent months parents of students at Altama complained that their
children exhibit an unusually high incidence of symptoms not readily classified as
"normal" childhood illness. There are no real standards for gauging
environmental illness. However, the immediate proximity of the dumpsite raises questions
of public safety at the school. Also, during November, 1992 the county public works
department indicated that ditch spoils from dredging operations were deposited on school
property for several years. Since the ditch tests positive for toxaphene at levels up to
435 parts per million (ppm) a decision was made to test the playground for toxaphene.
The testing took place on February 6, 1993. About 15 people observed the soil sampling.
Participating were representatives of the EPA, Hercules, Inc., the School Board, the Glynn
Environmental Coalition, and other involved individuals. RMT Inc., the company
implementing the Remedial Investigation, performed the soil sampling.
Seventeen samples were collected from the playground area. Two additional samples were
taken from the front grounds near the school entrance. Samples were not collected from the
area between the 009 landfill and the playground. Only one of the samples came from the
surface of the dredge piles immediately adjacent to the fence surrounding the playground.
Based on the sampling pattern, this study was designed solely to test the safety of the
playground.
Every scientific study is designed to answer very specific questions. Error can arise from
several sources. The most common problem is the lack of meaningful controls.
"Controls" are positive or negative known values that are compared to the
observations under study (called "variables"). The more complex the study, the
greater the need for verifiable control observations.
The sampling plan also requires careful design. The number of observations, the amount of
material sampled, the method of collecting the sample, handling procedures, and the
location of the samples are all taken into consideration when reaching a conclusion.
Finally, error can result when the amount of information is too limited to support the
conclusions.
During the Altama playground study RMT followed generally accepted methods for collecting
and preparing samples. They established a sampling grid throughout the playground and
collected the material at reasonable intervals. Sufficient controls were undertaken to
ensure that the chemical analysis was fair and accurate. Three different laboratories
examined most of the samples, which further minimized any potential bias. All of the
samples were found to be negative for toxaphene. Is the Altama Elementary School safe from
Toxaphene? It is fair to say that the playground is toxaphene free and therefore safe.
However, samples were only taken from the playground. Other areas remain untested around
the schoolgrounds. "Extrapolation" is the term used to describe the process of
applying a few observations to an area larger than actually studied. There are well
established rules governing the use of extrapolation. The first step is the development of
a model with full definition of the expected results and the statistical treatment.
Observations are then collected and compared to the expected results. Only if there is
substantial agreement between the model and the observations can the extrapolated data be
used to draw conclusions on unstudied areas.
Two frequently asked questions regarding the testing are:
Is there an actual model for toxaphene occurrence at the 009 site? The sampling
outside of the landfill cells has followed no fixed plan. There is no apparent attempt to
define the range of toxaphene when positive areas are observed. At this time there is no
real pattern to the occurrence of positive samples outside of the landfill. Most of the
information used to estimate toxaphene occurrence at the site is based on historical
records. However, as late as 1992 soil samples tested positive in areas along Benedict and
Nix roads; areas considered "historically" free of toxaphene. There appears to
be no working model for predicting the occurrence of toxaphene outside of the site.
Does Toxaphene occur on school property? Soil sampling in the areas around the site
show that SB-16, located on the east side of the drainage ditch, has a level of toxaphene
at 1.5 ppm. SS-24, on the east bank where the ditch bends to flow past the school, also
shows toxaphene at a level of 0.74 ppm. These locations are identified by schoolboard
members as school property. No sampling has been done to find the full extent of the
contamination in this area. Also, concern over sample area SB-4 in the drainage ditch
adjacent the school still exists. The area has tested positive in the past. A study in
1990 found the sample to be negative, however, the detection limit was set too high to be
a useful observation. For unknown reasons the site was excluded from retesting in 1991.
During the September 1992 public meeting, EPA officials claimed that this sample was
retested and found to be negative. However, this cannot be confirmed from any data
provided to the community. Moreover, this sample appears on some charts and not others. It
is very unclear if this important sample location is actually monitored. The presence of
contamination on the school side of the ditch is in conflict with the EPA model for the
area that says toxaphene cannot be dispersed across the ditch to the schoolgrounds, even
though it has repeatedly been found.
It is reasonable to conclude that the playground is toxaphene free and safe for the
children attending the school. It is, however, not valid to assume that the schoolgrounds
are completely toxaphene free. The areas of the schoolyard next to the site appear on
charts as contaminated with toxaphene. The full extent of the contamination is still
unknown. The drainage ditch has historically been contaminated and is not fully monitored.
The spoil piles deposited on school property remain untested. Based on the history of
sampling at the site it would not be practical to extrapolate the occurrence of toxaphene
based on this study. Also, this round of testing was not designed to negate parental
complaints over their child's symptoms. Until the area is fully tested there is still
reason for concern.
Record of Decision
The Environmental Protection Agency recently released the Record of Decision (ROD) for
Remedial Action of the Hercules 009 Superfund Site. The EPA chose in situ stabilization at
the dumpsite combined with a cap over the contaminated area. The ROD is based on nine
criteria established by law. The EPA did not consider any off-site methods of sludge
storage or treatment. Treatments the EPA did consider are:
No treatment- leaving the site as is, except for occasional monitoring;
RCRA cap- covering the site only with a "multimedia" cap of soil, fabric, gravel
and clay;
In situ stabilization- the "in place" underground mixing of sludge and cement;
Chemical Extraction- removing the sludge followed by use of chemical solvents to separate
toxaphene from soil and on-site redisposal of the concentrated toxaphene.
The EPA chose in situ stabilization as the best method of meeting the feasibility
criteria. However, on review of the discussion in the decision it appears that only one
criteria-- cost effectiveness-- was the determining factor.
Feasibility Criteria Under the Comprehensive Environmental Response Compensation and
Liability Act (CERCLA) are:
 | Overall Protection of Human Health; |
| Compliance with all laws; |
| Long-term Effectiveness and Permanence; |
| Reduction of Toxicity, Mobility or Volume; |
| Short-term Effectiveness; |
| Implementability; |
| State Acceptance; |
| Community Aceptance; |
| Cost Effectiveness. |
Overall Protection of Human Health
This is the single most important factor governing the outcome of remedial action at the
site. To understand the relative advantages and disadvantages consider remedial
opportunities on a scale of 1 to 10. Cleanup to background levels is a "ten"
since there is no chance for any human to be endangered by chemicals in the dump. No
action is a "one" since the current risk scenario is unchanged. Capping and
stabilization still leave the material free to interact with the environment;
consequently, they carry about the same amount of risk (roughly a "three").
Extraction/reburial, although not ideal, would offer far better chance of containment, and
is a more tangible option (about an "eight"). So the choice of in situ
stabilization is not the best choice for containment since there is a chance that material
may still result in human injury over the several decades the site will remain toxic.
Short-Term Effectiveness
The EPA argues in the ROD that in situ stabilization offers greater protection of Human
Health since it reduces opportunities for dispersal during remediation. This is a very
short-term benefit at the expense of long-term effectiveness. The remediation period is a
few years at most. Since the dump will remain toxic for up to a century the long-term
effectiveness should be given greater priority.
Long-Term Effectiveness
The next phase of Remedial Action is a study to determine if stabilization will actually
work at the site. A small portion of a cell will be stabilized in situ and watched to
determine if movement of toxaphene continues. Until these studies are complete there is no
assurance that stabilization provides relief from any toxaphene erosion.
There is another long-term factor that was apparently not considered. In situ
stabilization will result in this dumpsite becoming a "sacrifice zone." No use
can be made of the grounds or the surficial aquifer for generations. The definition of
"effective" treatment is unmet when toxaphene is left in contact with the
aquifer, regardless of its form.
Reduction Of Toxicity, Mobility, Or Volume
In situ stabilization does not achieve a reduction in volume at the site. In fact, mixing
with concrete actually increases the volume by as much as 50%. In situ stabilization does
not achieve a reduction of toxicity at the site. The level of toxaphene drops at best to a
minimum average level of 400 parts per million, still quite toxic. The proposed site study
is necessary to determine if any decrease in mobility is achievable.
In contrast, extraction would result in immediate and verifiable reduction in mobility and
volume. Toxicity might be increased during the extraction process, particularly to site
workers. However, these workers will be in no greater danger than Hercules employees, site
neighbors with toxaphene in their yards, and individuals living near the Hercules plant.
Since Hercules, the EPA , and the ATSDR have all pronounced toxaphene safe for these
groups, this slight increase in exposure could not have been a consideration in the
decision. It is difficult to see any advantage gained from in situ stabilization over
extraction for this criteria based on information provided by the EPA.
Community Acceptance
The community did not voice support for the in situ remediation option. During the public
commentary period a majority of the community indicated a preference for chemical
extraction. Most residents felt that they had lived long enough in the proximity of toxic
waste. A minority agreed with Hercules that an RCRA cap was all that was required. Most
importantly, no one asked the affected residents if they would accept the potentially
greater risk from extraction for 2-3 years in exchange for generations of safety. Since
these individuals are bearing the brunt of potential danger from the site, their wishes
should be given greater weight in the decision process.
State Acceptance
The ROD cites State of Georgia approval of the in situ option. On the contrary, a letter
from the Georgia Department of Natural Resources dated October 26, 1992 actually asserts
nonconcurrence with the in situ stabilization option. The letter states five distinct
reasons for rejecting in situ stabilization and concludes: "...the cost of chemical
extraction is justified." A file memo from EPA Remedial Project Manager Alan
Yarbrough indicates that meetings between the EPA and GaEPD (the state Environmental
Protection Division) took place on December 22nd, 1992 and February 8th, 1993 resulting in
withdrawal of the nonconcurrence with in situ stabilization. This rescidence is in a
letter dated March 23, 1993 signed by Mr. Harold Reheis. These meetings were not announced
and the substance of the discussions are not a matter of public record. No information is
available on the review process used by the state to endorse in situ stabilization. Until
the state explains its decision to override community preferences it seems fair to assume
that the criteria of acceptance was not met as required by public law.
Compliance With All Laws
There appears to be no city, county, or state role at this dumpsite. Local officials have
not offered oversight or challenged jurisdiction. No other Federal agencies are presently
involved. Barring any civil action, the EPA can write its own code at the dumpsite
regardless of the remedial option chosen. This feasibility criteria is met for all the
remedial actions proposed at the site, and, therefore is not a determining factor favoring
selection of in situ stabilization over any other proposal. Curiously, this will be the
second time that Hercules, Inc. has complied with all laws and conditions for long-term
storage at this dumpsite. It is also the second time the state has endorsed an engineering
plan for control of toxaphene wastes at the landfill.
Implementability
All five of the considered options can be completed with existing technology. No
breakthrough developments are required to utilize any of the options. Implementability was
not a criteria for choosing one option over another.
Cost Effectiveness
In comparing extraction with stabilization the ROD states on pages 48-49: "
Alternative #5 [extraction] does satisfy the preference for treatment and does reduce the
toxicity and mobility of the contaminated media, but the greater than threefold cost
increase is not warranted since Alternative #4 [stabilization] will also protect human
health and the environment."
Clearly, from an engineering perspective in situ stabilization offers no particular
advantage. Stabilization leaves toxaphene in contact with the environment, only in a
different form. Cost effectiveness, not public safety or long-term stability of the site
appears as the determining factor in choosing the in situ stabilization option.
In Situ Stabilization
The concept of in situ stabilization is simple enough. A hollow auger is drilled into
the ground and cement is pumped down the barrel as the auger is withdrawn. The cement
hardens and the material is immobilized. However, if you have ever tried to mix an egg
yolk with milk, or a can of paint by hand, you will know that this simple concept can
require a great deal of energy.
In situ stabilization is only effective if the mixture is homogenous. The waste particles
must be completely suspended within cement. Literature provided by the EPA indicates the
stabilized block will fail if the waste particles are larger than one-quarter inch.
Particles that are very small may not be immobilized and can migrate out of the block.
Particles less than 74 mm (the width of the average human hair) were not immobilized. Much
of the toxaphene at the site occurs as "colloids" that are much smaller than the
minimum requirements for stability.
Cement materials are inorganic salts that do not mix with or bind organic materials, such
as toxaphene. Binders must be added to increase the adsorption of toxaphene to the cement.
There is very little information on the long-term stability of these cements.
The stability of the mass may be affected by repeated freeze thaw cycles. It is unclear
how many freeze cycles are too many. In the south there can be fairly large temperature
gradients between the surface and the upper level of the surficial aquifer during summer
and winter. It is unclear how these may effect the outcome of attempts to stabilize the
dumpsite.
The Department of Interior's Earth Manual indicates that concrete has only a limited
lifespan when in contact with groundwater. The proposed monolith will be, in some areas,
several feet below sea level. It is unclear how immersion will effect the long-term
stability of the site.
The Remedial Investigation shows a distinct tidal periodicity common to areas adjacent to
salt water marshes. How this may affect the lifespan of the monolith must still be
addressed. It is uncertain how much the volume of the dumpsite will increase from addition
of cement and additives. The ROD estimates about a 25% increase in volume, however this is
based on small bench scale samples. At other sites where the technique is employed
dilution ranges from the ideal amount of 15% to as much as 115%.
No meaningful information is available on the stability of organic chemicals in situ. The
EPA has failed to cite even a single example where in situ stabilization decreases the
leaching of organic wastes in a scientifically verifiable manner. The closest materials to
toxaphene examined are PCBs and pentachlorophenol. In one controlled study, PCBs actually
leached at a faster rate after stabilization. Another study concluded "... a firm,
decisive evaluation of the technology's ability to immobilize PCBs could not be
performed" (SITE: International Waste Technologies/Geo-Con In Situ
Stabilization/Solidification Applications Analysis Report; EPA/540/A5-89/004).
Putting aside questions of physical stability, there are some chemical effects that, at
least theoretically, may make in situ stabilization useful. In nature there are many types
of chemical bonds. The strongest types of bonds are called "covalent" bonds.
Toxaphene is a molecule of chlorinated camphene that has hydrogen, carbon and chlorine
atoms held together by covalent bonds. To destroy toxaphene all of the bonds need to be
broken. However, to detoxify toxaphene to harmlessness, only removal of the chlorine atoms
from the camphene chemical skeleton is needed. Some dechlorination occurs naturally,
although at a very slow rate. Currently at the landfill the toxaphene sludge is in
slightly acid media that does not favor natural dechlorination. Cement is usually strongly
alkaline. Dechlorination is often accelerated in alkaline conditions. This indicates the
possibility that in cement toxaphene may detoxify to camphene at a higher rate than when
untreated. Some landfills using in situ stabilization also employ pretreatment steps to
mix the waste with alkaline materials, such as potash or lime, that further enhances the
breakdown of the chemical after solidification (potash and lime are used in many household
products, particularly soaps, detergents and cleaners). Unfortunately, at this site
chemical fate studies were not performed so the rate of natural decomposition is unknown.
Also, the ROD does not indicate any studies that might verify this potential benefit of in
situ treatment.
Another class of chemical bonds are "ion" bonds that are much weaker than the
covalent bonds that hold toxaphene together. Most of the toxaphene at the site occurs as a
sludge of toxaphene adsorbed onto the surface of small particles. The force that holds
toxaphene to the particles is an ion bond. Ionic binding is under environmental influence
and is weaker or stronger in response to relatively slight changes in temperature, pH
(acidity or alkalinity), and the concentration of surrounding chemicals. For instance,
toxaphene will not stick tightly to particles when in pure distilled water. Slightly
acidic conditions actually favors the release of toxaphene from sludge particles, while
strongly alkaline conditions can make toxaphene stick much tighter. Changing the matrix
from slightly acidic to strongly alkaline may actually decrease the mobility of toxaphene,
an important factor considering the possibility the embedding material may begin failing
in less than a generation. Unfortunately, the mobility tests and matrix descriptions in
the Remedial Investigation are so poorly done that it is impossible to tell if this
advantage will be realized at the site. And again, the ROD is vague as to whether or not
this information will be provided from subsequent studies.
Clearly, previous studies conducted at the dump are of very poor scientific quality. The
experimental designs allow for only limited conclusions. The lack of adequate positive and
negative controls would exclude the data from publication in most scientific journals. In
combination with the meager information available for in situ treatments it is difficult
to understand how the EPA will determine if the stabilization process actually works.
The ROD does provide two contingency plans for handling failure of the in situ
stabilization. In the event that groundwater at the site becomes contaminated with
dumpsite chemicals there is a backup plan to cycle ground water through activated charcoal
filters. If toxaphene migrates from the site during the preliminary study then the site
would be remediated using extraction technology.
What is the pass/fail criteria? Section 9.0 of the ROD, subsection A.3 discusses
performance standards. The criteria is given as: "A 90% reduction in concentration or
mobility of the contaminated soil after treatment is the treatment target." The
leachate procedures used during the Remedial Investigation measured desorption (release)
of toxaphene from sludge particles. The range of values (termed the "Kd") varied
from less than 170 to more than 24,000 depending on where the sample was taken from the
dumpsite. It is difficult to understand how the EPA will obtain a value of 90% change from
a range spanning 3 orders of magnitude. Using the Kd as a measurement for flow of material
in the environment is well understood for water soluble materials. However, for materials
with high and variable Kds this index has been historically unreliable.
Can cracks, gaps, and fissures be detected in a quantitative fashion? How will the portion
of the monolith in contact with the water table be monitored? How will samples be taken
without damage to the monolith? Of particular concern is the base of the monolith in
contact with the water table. The plan is to drill through the sludge, through the
bentonite layer and into the stumpdirt underfill. However, the RI indicates that woodchips
are a substantial component of the stumpdirt. The background literature states that
woodchips are contraindicated when using in situ treatments since the decay of the chips
leads to premature failure of the surrounding block. Further, particles over one-quarter
inch are also to be avoided in the mixing process. The remediated areas most likely to
fail and most critical to the success of this project are also the most difficult to
assay.
The nature of toxaphene and the presence of such a great concentration of a single
chemical presents difficulties not encountered at other sites. Also, the proximity of so
many homes and businesses places restrictions on site activity. All of the potential
remediation methods were "experimental" when applied to this site and each had
both positive and negative attributes. Although there are a great number of unanswered
questions surrounding the in situ process the proposed site study is a prudent approach to
finding a solution. However, it is essential that the preliminary site studies yield real
and valid data on the usefulness of in situ stabilization at the 009 landfill before
applying the process to the entire dumpsite.
Chemical Mobility
The goal of stabilization is to "attenuate" or change the ability of the
chemical to move in the environment. Above ground it is relatively simple to control
erosion. But below ground the technology must inhibit "leaching," the process
that chemicals move in response to underground currents of water. The aquifer is a mixture
of porous sand and clay that water, and chemicals, percolate through. As chemicals move
within the porous media they also bind to the particles. The measure of the ability to
bind and release is called a "Kd"- scientific shorthand for "distribution
coefficient" (more jargon for the amount of chemical, in milliliters per gram,
released, or "desorbed," over time).
A Kd of around 1 means that the chemical will flow about the same speed as the surrounding
water column. If it takes 10 years for water to flow underground from point A to point B
then a chemical of Kd = 1 will also take about 10 years to move the same distance. The
higher the Kd number, the longer the lag time.
A Kd is a reflection of both the nature of the chemical, the surrounding solids, and the
liquid media. The same chemical will show very different adsorption to sand or clay. Also,
since the Kd is a combination of ionic bond effects and solubility there are acidity and
temperature aspects as well. 70 years is a long period of natural history to predict the
mobility of a chemical in soil, especially in an urban area.
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