SITE INFORMATION AND CORRESPONDENCE

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Recommendations 6421 Paddock Place,Lodi Project 166.2 November 16,1993 Page 2 3) Exposure Assessment - • Analyze contaminant releases • Identify exposed population • Identify potential exposure pathways • Estimate exposure concentrations for pathways • Estimate contaminant intakes for pathways 4) Risk Characterization - • Characterize potential for adverse health effects to occur from each chemical identified -- Estimate cancer risks -- Estimate non cancer hazard quotients • Evaluate uncertainty • Summarize risk information Information to be included in the database for this risk assessment is the following: • Soil sample collection and testing of the native soils around the tank farm; • Evaluation of the sites geology and hydrology; • The construction of the water well, depth to drinking water aquifer, and well testing data; • Factored into the exposure assessment calculations would be assumptions that the tanks would be removed by December 1998 and that if hydrocarbons are present in the soil around the tanks then would also be removed. The goal of this work would be to document that if the site was closed at this time, with no remedial work, the extremely low levels of petroleum hydrocarbons present in the groundwater would have no effect on public health. Alternative 2: Aquifer Testing/Groundwater Pumping As a means for assessing the groundwater hydrology of the site Geological Technics recommends that a 48 hour (minimum) aquifer test be performed. The aquifer test can evaluate the hydraulic characteristics of the shallow groundwater aquifer and quantitatively assess the chemical content of the groundwater. In the event that the petroleum hydrocarbons detected in the groundwater in MW-3 (refer to the attached monitoring report by Del-Tech) are limited in extent to the immediate area around the tank farm and MW-3, these hydrocarbons can effectively be pumped out in a short time period.