The Superfund site was a former chemical distribution facility in northern California that has chlorinated solvents, petroleum compounds, 1,4-dioxane and lesser amounts of metals and pesticides as contaminants of concern (COCs) in both shallow and intermediate aquifers. The site has already went through product removal, electrical resistance heating (ERH) and an ISCO pilot test. The Feasibility Study includes evaluation of both natural attenuation (NA) and enhanced biodegradation as possible portions of the final polishing remedy. Future land use has not been finalized but the remedy may have to meet MCLs despite being in an industrialized area and TDS content making the aquifer unusable for drinking water. The historical high concentrations and current moderate concentrations of petroleum hydrocarbons maintains both aquifers in an anaerobic state, creating a dissolved arsenic problem from the natural high levels of arsenic in California soils. The remedy will be complex.
