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spread from the source. The remaining soil contamination could eventually reach groundwater (oil was not present in the groundwater in November 1996, and was found floating on the groundwater in MW-2 in September 1998). Therefore, the only remaining concerns associated with the used oil USTs are the removal of any floating oil from MW-2 and the determination of the extent of contamination in the groundwater. A schedule of the removal of any floating oil in MW-2 is located in Appendix A, Table 2. 4.2 Diesel USTS Two-10,000 gallon diesel USTs were from removed the site by Station Equipment Co., Inc. (SECT) on 4 September, 1998. Soil samples were taken from under the ends of each tank, from piping on each tank and from the stockpiled soil. Analytical results are summarized below: Location TPHd Benzene Ethylbenzene Toluene Xylenes (ppm) (ppb) ( pb) b ( b Tank 1 -- West End 6.1 ND ND ND ND Tank 2 -- West End 95 ND ND ND ND Tank 1 -- East End 14,000 ND ND ND 980 Tank 2 -- East End 6,600 ND ND ND 580 Piping — Tank 1 990 ND ND ND ND Piping -- Tank 2 ND ND ND ND ND Stockpile #1 3,600 ND ND 7.7 22 Stockpile#2 2,200 ND ND 48 68 The release of diesel fuel at the east end of the tanks is evident, particularly in tank 1. The principle concern is whether this has reached the groundwater. Of lesser concern is the lateral extent of contamination in the soil. 5.0 SURVEY OF WELLS A survey of domestic, municipal, agricultural, industrial and any other wells within a 2000 foot radius of the site (Figure 4) was conducted by El's subcontractor, Helmick and Lerner. Additionally, El contacted municipal water suppliers, nearby industries and the San Joaquin County Public Health Services, Environmental Health Division to complete the survey of wells within 2000 feet of 3105 South El Dorado Street. It was determined that California Water Services does not have municipal wells within this radius. Environeering, Inc. Project No. 98-012.01 4