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Final Remedial Design Report for the 009 Landfill NPL Site
March,1998

 

     

      The "Final Remedial Design Report for the 009 Landfill NPL Site" and Workplan provide more

      information on the proposed cleanup than available in past documents. Although it remains unclear

      if the actual cleanup can meet Environmental Protection Agency (EPA) guidelines, the documents

      do outline a realistic plan for remediation and closure of the site.

 

      The documents offer more construction details and less of the philosophy that has characterized

      previous attempts to meet the EPA's requirements. However, in one section the Plan provides

      extensive preparations for a massive "blow in" of the base of the landfill that would endanger

      workers, while the illustrations make it clear that neither equipment or personnel will be

      anywhere near the actual digging. Also, work statements indicate that treatment will occur during

      the lowest cycles of the water table, and no hydraulic data is provided showing upwelling as a

      major potential problem. Yet, the documentation gathered during the cleanup is to justify shallow

      remediation due to the "threat" of upwelling or implosion. Finally, the Plan states that all EPA

      criteria will be met during remediation. But, there is no place in the Construction Management

      Plan or on the In Situ Stabilization Checklist for verifying that the EPA’s soil limits of 76 ppm

      toxaphene has been reached.

 

      This plan should retard toxaphene movement in the environment. However, if implemented as

      written, it will likely be called a failure since without verification data it will be impossible to

      know if the target levels were reached.

 

      Background

 

      The Hercules 009 Landfill in Brunswick, Ga., contains waste products from manufacture of the

      pesticide toxaphene. Toxaphene increases tumors in animal studies, and has toxic effects on the

      liver, immune system, and kidneys of a variety of animals. The waste left at the 009 site is

      presumed to have these same effects.

 

      The site was closed in 1980, and has been the subject of an Environmental Protection Agency

      Superfund project since the mid-1980s. Recently the final plans for the "remedy" (the engineered

      closure) for the site were provided to the Glynn Environmental Coalition (GEC) for review.

  

      Record of Decision

 

      In 1993 both the EPA and Hercules, Inc signed a Record of Decision or "ROD" agreeing to certain

      conditions for closing this site. Overwhelmingly, the public favored complete removal of the

      toxaphene waste from the site near the mall on the Golden Isles Parkway. The EPA considered

      removal, but found that it was too costly and risky to exhume the waste. Accordingly, the EPA and

      Hercules offered the next best thing: complete encapsulation of the waste with concrete. The

      overall design was for the entire area to be treated in situ (or "in place") with a cement

      formulation that would solidify and exclude water from entering the concrete monolith. With a

      suitable cap (originally a clay cap) and a vegetative cover the structure should last for many

      decades. Since toxaphene has an environmental half-life of at least 10 years this structure, if

      properly built, should outlast the chemical with only small nontoxic releases of degraded

      toxaphene over time.

 

      Changes to the ROD Design

 

      The three main aspects of the EPA’s remedy are: covering the structure with clay; exclusion of

      toxaphene migration to the groundwater; and, complete encapsulation of all soils having greater

      than 76 ppm toxaphene.

 

      Covering

 

      At the time the ROD was drafted it was not expected that there would be such extensive removal

      off-site at the schoolgrounds or in the adjacent neighborhood. At this time there are nearly 16,000

      cubic yards of soil contaminated with a low level of toxaphene that must be added to the

      remedy. The contaminated material from the neighborhood and schoolgrounds will be placed on

      the surface of the landfill after in situ treatment and compacted to form a dense overlay. This

      makes the area slightly higher than originally called for and acts as an extra buffer zone. The Final

      Plan calls for a 1-foot thick cap of compacted soil/cement mixture in place of the estimated

      2-foot thick layer of clay originally designed in the ROD. The purpose of the cap is to protect the

      surface of the solidified landfill and aid in shedding water from the site. The soil/cement layer

      should provide the same water exclusion as the originally planned clay layers.

  

      Groundwater

 

      This version of the plan is far more comprehensive in protecting groundwater during and after

      treatment. There are provisions for treatment of the "perched" water trapped in the landfill cells,

      and monitoring during the stabilization process. The Plan states that remediation will occur during

      periods of the lowest level of local groundwater, which should also maximize toxaphene

      encapsulation and strength of the monolith. If followed, the plan provides a high degree of

      confidence that groundwater will be protected during the cleanup.

 

      76 ppm?

 

      The ROD sets a goal for full concrete encapsulation of subsurface soils containing 76 ppm

      toxaphene and higher. During the Remedial Investigation subsurface soils were mapped for

      toxaphene concentrations and a depth profile generated for the waste containment cells.

 

      The Final Plan was expected to use this subsurface soil data to plan the depth of in situ

      stabilization. However, there does not appear to be any depth charts in the material provided to

      the GEC. The charts indicate areas where remediation will not occur, as opposed to providing

      target depth penetration.

 

      The Plan spends a great deal of time discussing a catastrophic "blow in" of the base of the landfill.

      This is detailed in pages 30 through 40 in the Report. Under this remarkable scenario water erupts

      in artesian fashion immediately on reaching the landfill base. Rapidly the bottom disintegrates and

      with incredible speed the bottom turns into quicksand and the equipment and workers tumble in

      the ever-widening pit. According to Hercules, even the merest hint of water infiltration requires

      an immediate halt to toxaphene cleanup in order to save the workers from this horrible fate. The

      EPA’s attitude suggests they actually believe this far-fetched plot.

 

      The workers who built this pit must wonder at this scenario. They walked all around inside the

      open pit for years with no hint of the mud geyser Hercules says is lurking just below the surface.

      In all of the hundreds of well and soil samples there was never anything to suggest this outcome.

      Other than an indication of admixture dilution in one sample point of the field trial there is no

      data to support the disaster hypothesis. However, despite the obvious fact that such an unstable

      floor is totally unsuitable for a concrete stabilization structure the EPA seems content to allow this

      disaster scenario to dictate cessation of the cleanup

 

      This cleanup can only be called a success if there is actual scientific proof of meeting the 76 ppm

      target. That proof can only be provided by testing a representative number of soil samples from

      the untreated soils beneath the in situ stabilized areas. There appear to be no provisions for

      providing this data in the current Workplan.

 

      Conclusions

 

      Overall this plan is a major step forward, but the Checklist for halting in situ treatment is based

      on a highly imaginative and overblown "threat" to the environment. In an odd juxtaposition of

      roles that portion of the project utilizes a reversal of the "sky is falling" (e.g.; "the bottom is

      dropping") mentality to justify a minimum cleanup. Just as it is incorrect to overstate the potential

      threat from residual toxaphene it is equally incorrect to overstate the potential threat from water

      intrusion.

 

      The EPA is urged to develop a comprehensive depth target profile for use in guiding remediation.

      This should be based on earlier sampling data showing the 76 ppm limits of both toxaphene sludge

      and toxaphene migration. These guidelines should be added to the Checklist and the Construction

      Management Plan. Further, the EPA is urged to provide plans for sampling a representative area of

      the landfill to show that significant toxaphene does not remain in contact with groundwater in

      untreated areas beneath the in situ stabilization. This sampling event should also be part of the

      overall Management Plan.

Written by R. Kevin Pegg, Ph.D.; edited by Dr. Mary S. Saunders. Copies of the report are available from the GEC, at the Glynn County library, or at www.enviro-isues.net  on the Internet. 

"This project has been funded wholly or partly by the U.S. Environmental Protection Agency under Assistance Agreement Number V994050-92-0  to The Glynn Environmental Coalition, Inc. The contents of this document do not necessarily reflect the views and policies of the U.S. Environmental Protection agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use."

 

 
   
   

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