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Kennedy/Jenks/Chitwn Mr. Charles Whitworth . Cal -Farm Supply 14 July 1989 Page 2 As part of pesticide handling operation, a portion of the facility was used for the dilution of bulk DDT to an application strength mixture. Bulk DDT was delivered to the site in concentrated form and was diluted or cut at the Cal- Farm facility with an inert material . It was reported that the standard operation for cleaning the formulation room floor was to sweep the excess DDT } out of the southern door of the building. I Previous sampling performed by Roy F. Weston, Inc. indicated that nitrates and total petroleum hydrocarbons were present in the shallow soils zero to three ' feet below the ground surface. However, analysis of a reconnaissance groundwater sample (WP-2) collected during that study detected 1350 mg/L of nitrates and 30.4 mg/L of total petroleum hydrocarbons (TPH) . It is assumed that this analysis was from a grab sample of groundwater collected at the site from either a soil boring or a reconnaissance probe. Therefore, on the basis of the water sample, these two chemicals may be present in groundwater at this site, although none of the soils sampled during the Roy F. Weston, Inc. study indicate a source area. The nitrate concentration in the water sample exceeds the 10 mg/L as nitrogen (45 mg/L as nitrate) level set by the EPA for Drinking Water Standards Nitrate present in the groundwater may be a concern to regulatory agencies. Although there are currently no standards for acceptable levels of TPH in ti groundwater, the primary concern with petroleum fuels is generally with the gasoline constituents benzene, ethylbenzene, toluene, and xylenes, and not with petroleum hydrocarbons as a class of chemicals. Therefore, to better define the extent of the problem, analyses for benzene, xylene, toluene, and ethylbenzene (BXTE) were included in the work plan for the present j investigation. On the basis of the results of Roy F Weston, Inc 's sampling, additional soil and groundwater samples were proposed in the work plan for analysis of TPH, BXTE, and nitrates. Based on the review by the Department of Health Services on the original work plan, 13 discrete soil surface soil samples were added to the work plan. These samples, randomly located across the yard, were collected for a wide range of pesticide analyses to help define the distribution of pesticides that may be present in the soil . The DHS also recommended that continuous soil samples be collected for the purpose of lithologic description of site soils during drilling. Continuous sampling was added to the scope of work performed in accordance with this request. Three storage trailers are present on the site (see Figure 3) and were reported to contain unused quantities of pesticides. One of the materials . reported to be in the trailer was the product Sllvicide Initial research of I