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'%Wo ,,/ <br /> Project No.E8062.WTP Phase 11 Environmental Site Assessment/Lathrop,CA October 21, 1999 <br /> r <br /> 3.2 Laboratory Analytical Methods and Results <br /> The soil samples were transported under chain-of-custody documentation to GeoAnalytical <br /> Laboratories, a California State-certified hazardous waste testing laboratory in Modesto, <br /> California (Certification No. 1157). The samples were analyzed for organochloride pesticides <br /> ., and metals arsenic, lead and mercury using Environmental Protection Agency (EPA) Methods <br /> 8080, 7060, 7420, and 7471. Laboratory analytical results of the samples reported no detectable <br /> concentrations (below laboratory detection limits) of organochloride pesticides. Arsenic was <br /> detected at concentrations ranging from 8.4 milligrams per kilogram (mg/Kg) to 19.5 mg/Kg. <br /> Lead was detected at concentrations ranging from non-detectable to 7.0 mg/Kg. Mercury was <br /> reported as non-detectable with each of the soil samples. <br /> 4.0 DISCUSSION <br /> 4.1 Metal Impacted Surficial Soil <br /> The detected concentrations of lead are within background levels for the native soil, and are <br /> considered below levels requiring further action. Arsenic was detected at concentrations higher <br /> than background levels, but not above the action level of 25 mg/Kg. <br /> 4.2 Background on DDT and DDE <br /> DDT and DDE were the most common and widely used chemicals for controlling insects on <br /> agricultural crops and controlling insects that carry diseases such as malaria and typhus. The US <br /> EPA banned all uses of DDT, except for public emergency in 1972 primarily because amounts <br /> were bio accumulating in the environment and because it was revealed to cause cancer in <br /> laboratory animals. Technical DDT is primarily a mixture of three forms (p,p'-DDT, op'-DDT, <br /> _ and o,o'-DDT), all of which are white, crystalline, tasteless, and almost odorless solids. DDE is <br /> found in small amounts as contaminants in technical DDT and is a breakdown product of DDT as <br /> well. <br /> 4.3 Pesticide Impacted Surficial Soil <br /> _ The California State Environmental Protection Agency (CAL EPA), Toxic Waste Division states <br /> that concentrations greater than 1.0 mg/Kg of the most commonly used pesticide (DDT) and the <br /> breakdown product(DDE) is considered a hazardous waste in the State of California. <br /> Organochloride pesticide concentrations at the subject site were below detection limits based on <br /> the soil sample analytical results; therefore,no action is required according to the CAL EPA. <br /> TERRASEARCH, inc. Page 5 <br />