TAG reports: Volume 3, Number 1; October,2001
Workplans for the Terry Creek Superfund Remedial Investigation
Overview
The Glynn Environmental Coalition received for review: the Terry Creek Work Plan for the Remedial Investigation/Feasibility study, the Sampling and Analysis Plan, the Quality Assurance Plan, and the Closeout Report Sediment Removal Action report, all dated July 2001. These documents cover past field investigations, document the partial removal action, and propose new work for the site.
The Sediment Closeout Removal Action report provided details on the removal, air-drying and land-filling of contaminated sediments. About 30,000 tons of sediment were removed and redisposed.
Overall, the work plan is of exceedingly poor quality since the plans fail to provide methodology for toxaphene analysis and calibration. Important receptors (animals threatened by toxins) seem to be ignored, and there is a complete lack of two important studies for subsurface soils and sediment transport. Any Remedial Investigation resulting from these plans will be unscientific and ineffective for developing Remedial Alternatives.
Background and Removal Action
The Hercules Terry Creek Superfund Site in Brunswick, Georgia is an estuarine marsh system formed from the confluence of Terry and Dupree Creeks where they interact north of Torras causeway. Once an important fishery, this region is now heavily contaminated with manufacturing effluent dumped through open trenches from several sources, most notably Hercules Inc. Past dredging to remove silt build-up has spread the contamination over wide areas.
By far the largest environmental problem in the Terry Creek site is toxaphene contamination from Hercules. Organizations such as the Environmental Protection Agency and the World Health Organization regard toxaphene as one of the worse Persistent Bioaccumulative Toxic Pollutants. Toxaphene is a known poison and carcinogen with a long environmental life.
Recently the site was the target of a removal action. An area of about 5 acres was excavated, air dried and transported away. The area was divided into removal zones called: pre-weir (7,445 cubic yards); post-weir (9,384 cubic yards); outfall mouth (10,111 cubic yards); and the creek zone areas (total creek zones: 8,208 cubic yards). The total cubic yardage removed is given at 35,148. Note that the original estimate for these areas from a preliminary study was 25,666 cubic yards, so there was nearly a 40% underestimate of the true volume from the preliminary studies.
The Broadhurst Landfill in Jessup, Georgia received the 1,200 tons of excavated sediment from the first phase of the removal action; the Superior Landfill in Savannah, Georgia received 28,000 tons of contaminated sediment from the second phase.
The sediment excavation was necessary to remove the highly contaminated soils around the effluent discharge ditch. However, the removal methods were controversial. Before hauling to a landfill, the material was air-dried in open piles on the shore. Toxaphene binds tightly to soil particles while wet, but can volatilize (be transported by air) when the soil particles dry. Some limited air monitoring was performed. No high levels of toxaphene were observed during the air monitoring. At one point fugitive dust clouds exceeded performance levels. That is the type of conditions where toxaphene volatiles can occur. It does not appear that air was monitored for toxaphene during that period; however, dust suppression was initiated to reduce the chance for contamination spread. Toxaphene aerosols have environmental implications for freshwater contamination in the Great Lakes region. Air-drying reduced Hercules transportation costs.
Remedial Investigation Workplans
The Superfund Process involves separate steps of Remedial Investigation (RI), Feasibility Study (FS), Record of Decision, Consent Decree, Remedial Design, and Remediation. These studies are intended to fill the legal requirements for a RI/FS. The documents are in three parts, an overall Work Plan, a Sampling and Analysis Plan (SAP) and a Quality Assurance Project Plan (QAPP). The plans are supposed to provide increasing detail on the specifics of testing. Actually, as reviewed, the plans contained sections that were merely “cut and pasted” between all of the documents, and omitted much of the critical detail needed for evaluation.
Toxaphene testing
protocol
For all practical purposes there is no information provided on toxaphene analysis. There were vague references to the discredited “Toxaphene Task Force” (TTF) methodology, a method favored by Region 4 EPA but used nowhere else in the world. The TTF method is known to underestimate toxaphene congeners (toxaphene is a mixture of over a hundred closely related chemicals). We would have expected the SAP to indicate where the samples would be taken and the QAPP to tell us how the samples would be treated, but the sections did not contain any information on the analysis. Curiously, there was a calibration procedure for toxaphene standards in the QAPP that was different than the Toxaphene Task Force specimen methodology mentioned in the workplan. The calibration protocol (SV0-51) indicated that the “three largest peaks for toxaphene” would be used in calibration. That differs from Region 4’s TTF method, which uses a highly biased “back-half” method of choosing analytical peaks. If the method SV0-51 is used for calibration and the TTF method for analysis then all of the resulting data will be incorrect.
There was mention of an acid cleanup for soil toxaphene testing, however the QAPP did not provide a relevant protocol. Since toxaphene is a mixture of over one hundred chemicals the acid treatment can selectively reduce some components, making the assay difficult to interpret. We expected to see protocols for acid testing of the analytical standards, but all of the acid cleanup protocols were omitted from the QAPP. The plan also noted (page 20 of the QAPP) that there were serious problems with toxaphene measurement: “…for some COPC’s [contaminants of potential concern](e.g. toxaphene), it is known that the analytical detection limits typically cannot meet the measurement quality objectives (i.e., higher than EPA Region IV screening levels).” Based on this observation by the study’s authors, methods should be modified so the investigation measures toxaphene at legal levels.
Workplan lacks
studies on subsurface soils
This workplan fails to implement studies on subsurface soils-- soils below 3 feet in depth. The work plan argues that the subsurface soils are not in contact with humans and biota. While this argument can be true for some fenced and restricted terrestrial sites, the statement is false for marsh ecology. The subsurface soils are widely used for burrowing crustaceans, mollusks, and annelid worms. These organisms often have feeding cycles of moving from the subsurface to the surface where they become prey. In addition to contributing to food-web toxins, the subsurface dwellers move contaminated soils more effectively than weather and diffusion phenomena. For this system, the subsurface soils should be included in all remedial studies.
Workplan fails to
include important receptors
As part of the RI/FS process an environmental risk assessment is done. The purpose is two-fold, to provide estimates of the severity of present day impact on wildlife and to gauge the effects of cleanup options on future impacts. The method involves identifying “receptors”- usually animals that use the marsh as habitat. Unfortunately, the plan is not well written and may not study some important receptors. We could not find relevant information on modeling studies for birds, reptile or mammals in the SAP or QAPP although they are mentioned in the work plan as receptors. Subsurface soil receptors were not included in any work plans. It is very unusual to omit all of this information from the sampling plans, and to fail to discuss the statistical models in the QAPP. Either the entire set of plans need to be overhauled and resubmitted or the ecological studies submitted as a separate plan.
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