Koppers Onsite Soil

Surface Soil Concentrations

As a result of the activities at the Koppers Site over the past 90 years, the chemicals used in treating wood have contaminated surface and subsurface soil. The primary chemicals of concern for risks associated with directly contacting the contaminated soils include arsenic, PAHs, and dioxins.

Currently, surface soils over most of the Koppers property exceed commercial/industrial soil cleanup target levels (SCTLs). In the western portion of the site, the contamination appears to be primarily near the surface (upper 2 feet). In some areas, particularly near the sources, the soils may be contaminated to the water table and below.

The “Addendum to the Revised Data Summary Report dated October 16, 2007 for the Koppers Inc facility in Gainesville, Florid”. (AMEC, March 16, 2010) present maps of both surface and subsurface soil data for dioxins, arsenic, PAHs (and Benzo(a)pyrene, and pentachlorophenol. It is from these figures that the areas of the site where the contamination primarily near the surface.

Note that these maps do not incorporate historical data, or concentrations reported in source area investigations.

The proposed plan identifies several other COCs for on-site soils, however, these are not on figures, and do not necessarily coincide with those identified in the risk assessment. In addition, no comparisons have been made to leachability criteria.

Proposed Remedy

Cleanup Criteria for direct contact commercial/industrial onsite. The preferred remedy proposes regrading and covering on most of the site, excavation of “some” contaminated soil in non-source areas.

• Excavation of areas of contaminated soil in non-source areas on-site; consolidation of excavated soil to source areas to be capped
• Establishment of a low-permeability cap/cover over all four source areas, including the consolidated soil excavated from non-source areas (on-site or off-site)
• Surface grading and cap covers on approximately 83 of 86 acres on the Site property.
• Institutional controls to mitigate risks from exposure to Site soil, sediment, surface water or groundwater.