TAG reports: Volume 1, Number 2;
October, 1992
009 Superfund Site: Executive Summary of the Report to the Coalition
Overview
The following are reprints of the Executive Summary and Conclusion sections of the Report
on the Remedial Investigation/Feasibility Study. Copies of the full Technical Assistance
Report are available from the Glynn Environmental Coalition.
Executive Summary
This Technical Assistance Report reviews the Hercules 009 Superfund site Remedial
Investigation and Feasibility Study as part of the community oversight process. The
Remedial Investigation is a study of pollution, ecology, erosion, and potential long-term
health risks. The Feasibility Study uses data from the Remedial Investigation to plan the
cleanup.
The Remedial Investigation contains a site description, environmental studies, groundwater
and soil sampling surveys, and a health-effects model. The Site description understates
local urban growth. Ongoing construction projects, plans for nearby housing, and potential
effect of severe storms are not discussed. Although EPA considers urbanization in their
decision, the Remedial Investigation does not provide enough information for long-term
planning.
Soil, well, surface water and sludge samples were tested. Toxaphene is the main
contaminant, but other toxic chemicals (BTEX) are present. Several inorganic compounds
occur at high levels, possibly as part of the native geology. Some on-site test wells are
positive for toxaphene and samples from one containment cell show leaching into the water
table. At this time it appears that only small amounts of toxaphene waste are leaking from
dump. The degradation products of toxaphene were not determined, making it impossible to
estimate the half-life of toxaphene at the site.
Toxaphene is a class B-2 human carcinogen and causes damage to kidney, liver, nervous and
immune systems. Damage to juvenile development, such as underdeveloped organs and limbs,
may occur. Little information exists for effects of toxaphene on children, women or the
elderly. Toxaphene is very stable in the environment and chronic exposure is a safety
concern.
Chemicals move by volatility, leaching, runoff, and foodchain contamination. The amount of
toxaphene diffusing in air is too small to be hazardous. Since toxaphene dissolves poorly
in water, leaching effects will be minimal. Runoff is the major factor in toxaphene
movement at the Hercules site.
The sampling plan did not use traditional grid testing patterns. The borders were defined
mainly by interviewing workers who built the dump. Contamination from transport occurs in
the neighborhood and access road. Inadequate information on the extent of contamination
makes it difficult for the EPA to impose jurisdiction on the site. Underestimations of
soil volume may affect final clean up costs.
The Remedial Investigation uses a single study to model flow in aquifers beneath the site.
The study only considered chemical transport by laminar flow, although information from
residential wells suggests potential movement by "lens-effects." The water table
is in direct contact with the sludge layer and groundwater at the site contains toxaphene
at concentrations above the Action Limit.
The environmental studies measured biodiversity, plant stress, bioaccumulation and
effluent toxicity. Biodiversity involves counting species to determine environmental
stress. This biodiversity study lacks valid control sites and no conclusions can be
reached. The informal plant stress assessment was not a scientific study of the local
flora. Bioaccumulation occurs when animals store toxins. The bioaccumulation studies used
animals caught far downstream. No rationale was given for failing to examine nearby
specimens. Preliminary reports show sediment toxicicity in an EPA approved bioassay.
Later, the data was reanalyzed ignoring the period when fatality was observed. This
unscientific "loophole" in toxicity testing allowed incorrect conclusions. The
studies suggest possible long-term environmental damage from contaminated soil.
The Remedial Investigation focuses on modeling the "excess cancer risk" using
toxaphene studies in animals. Potential health effects such as organ failure and arrested
development are not part of the model. A study of exposed residents by the Toxic
Communications and Assistance Project, Albany State College, did report health problems. A
survey of soil contamination in the neighborhood detected toxaphene in every sample,
although not all samples were above the Action Levels.
Since Action Levels are not based on an understanding of toxaphenes effect on the general
population a more conservative estimate is needed to ensure the public health.
The feasibility criteria include: overall protection; legal compliance; cost;
effectiveness; reduction of toxicity, mobility or volume; and community acceptance. The
final criteria, state and community acceptance, remains to be judged by the Environmental
Protection Agency. At the September 10 public meeting the EPA favored in situ
stabilization. The EPA considered chemical destruction, immobilization, and extraction
methods in their decision. Chemical destruction reduces toxin to harmless compounds.
Immobilization methods solidify chemicals in soil-concrete mixtures. Extraction removes
the chemical from the soil.
Methods such as bioremediation, chemical destruction and incineration destroy toxic waste
products. From an environmental standpoint bioremediation is best, but not practical at
this site. The Resource, Conservation, and Recovery Act (RCRA) provides for more extensive
site securing methods than used in the past. One remediation alternative was installation
of an RCRA cap. At the Hercules dumpsite sludge layers are secured with dirt a few feet
deep at most. An RCRA multimedia cap would completely enclose the surface to reduce
erosion.
The EPA prefers in situ stabilization using underground mixing of concrete and dump
components to produce a solidified mass. Contaminated material from the drainage ditch and
neighborhood would be landfilled before in situ stabilization. This method generates less
airborne contamination than other methods. In situ stabilization is used for solidifying
inorganic contaminants, but not for complex organic chemicals such as toxaphene. The
concern is that soil-concrete will not be stable in marsh conditions. If the material
fails the only recourse is to remove the toxic solidified mass.
Chemical extraction removes contaminants by washing the soil with solvents. Clean soil is
reburied, the solvent recycled, and the concentrated toxaphene removed or reburied.
Chemical extraction is an effective cleanup operation. Chemical extraction and in situ
stabilization are experimental techniques and field results can differ from laboratory
studies.
Summary and Conclusions
The Remedial Investigation does not provide sufficient data to consider the
Environmental Protection Agency's proposed options 1-4 (no action, site controls, capping
only, and in situ stabilization). Only option 5, complete removal, can be considered based
on the merit of the scientific evidence in the Remedial Investigation. Considering all the
options, incineration is the only method that results in destruction of toxaphene at a
reasonable cost. Since thermal destruction requires positioning a portable incinerator
nearby, the EPA dropped this option due to anticipated community rejection. Chemical
extraction results in a clean site with no further environmental damage, although in the
short-term the site will be less stable. In situ stabilization will provide improved
near-term stabilization and results in less toxic byprocess of cleanup. Disadvantages of
in situ relate to questions of long-term effectiveness and a potential increase in toxic
volume. The remaining options of RCRA cap only, institutional controls only, and no
remediation should be rejected by the community because they are an insufficient response
to the potential health effects of the dump.
The Environmental Protection Agency's feasibility criteria should not be given equal
weight in considering options for remediation. The criteria of safety, or, the
"Overall Protection of Human Health and the Environment" is a greater issue than
cost and compliance. If there must be bias in a decision it should not be towards the
amount of money spent or regulations served.
A full copy of this lengthy report will be provided for download by FTP in November,
1995.
LINKS:
Jump to top of page
visit TAG Advisor R. K. Pegg's Homepage
Return to TAG table of Contents