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16 August 2001 AGE-NC Project No. 01-0852 Page 7 of 7 encountered in the former distillation area, also contained low concentrations of toluene, ethylbenzene and total xylenes. Again, additional samples collected in the area did not contain detectable concentrations of hydrocarbons. AGE found no connection to any of the suspected contaminant sources or other evidence that the encountered hydrocarbons are likely to be part of a significant release in the area. All of the shallow soil samples collected in the areas of the two former cooling towers contained detectable concentrations of hexavalent chromium with concentrations ranging from 1.0 mg/kg to 9.8 mg/kg.Two samples collected from 5 feet bsg in each of the two areas did not contain detectable concentrations of hexavalent chromium. The available data suggests a widespread, shallow impact to soil in the areas of the two former cooling towers that does not appear to extend significantly into the subsurface. The detected distribution of hexavalent chromium is suggestive of deposition by wind-blown spray from the cooling towers impacting the shallow soil, The available data does not appear to indicate a significant subsurface release of the contaminant. The detected concentrations are below the federal EPA Preliminary Clean-up Goals (PBGs)of 30 mg/kg for residential soil and 64 mg/kg Tor industrial soil,but do.exceed the California-modified residential PRG of 0.2 mg/kg. As the site is not likely to be utilized_ for residential purposes,-it seems unlikely that the California- modified PRG would be applied to the site. . �k In response to an AGE inquiry, a representative of the California Department of Toxic Substances. I Control(DTSC)could not offer an.opinion of the DTSC's level of concern with the concentrations detected without careful review of the sampling methods, location, etc. Based on the assumptions of probable source localities, interpreted method of deposition, sample localities, and contaminant concentrations encountered,AGE believes that-the hexavalent chromium concentrations encountered in the'shallow soil samples are representative of the actual concentrations remaining in place and that X remediation and/or cleanup of the impicted soil is not likely to be required. 7.0. LIMITATIONS Our professional services were performed using that degree of care and skill ordinarily exercised by environmental consultants practicing in this or similar fields. The findings were based mainly upon analytical results provided by an independent laboratory.Evaluation of the soil conditions at the site has been made from a limited.number of available data points (i.e. soil sampling points), and subsurface conditions may vary away from these data points. The absence of any potential gross contamination sources, historical.or present,- does not necessarily imply that the site is free of any contamination. This report only represents a"due diligence"effort as to the current environmental status of.the site. No other warranty, expressed or implied, is made as to. the professional recommendations contained in this report. Advpnced GeoEnvironmental;Inc.