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' G eolog icaCTechnus Inc Page 4 Groundwater Monitoring Report Project No 770 2 August 20,2001 ' 1.3 Laboratory Analyses ' The groundwater samples collected on June 27, 2001 were delivered to Sherwood Lab (Department of Health Services Certification No 1400), of Hilmar, California, for analysts Sherwood analyzed the three monitoring well groundwater samples for • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) by EPA method 602 • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) ' • TEPH- Diesel, Kerosene, Dielectric and Motor Oil by EPA method 3510/8015(M) ' Sherwood also sent the samples to Entech Analytical Labs Inc (certification #2346) for the analysis of Methanol, Ethanol by EPA method 8015 ' The detection limits for the above analyses are listed in Table 2 of Appendix A while the lab analytical results are presented in Appendix B 2.0 FINDINGS AND DISCUSSION The results of the groundwater sample analysis indicate the following ' • Diesel range petroleum hydrocarbons were detected in five of the seven monitoring wells MW-1, MW-4, MW-5, MW-6, and MW-105 • The field technician noted the presence of product sheen in well MW-5 • Minor BTEX constituents are present at levels ranging from <0 3 — 6 pg/l in wells MW- ! 3 and MW-6 • Gasoline, kerosene, and motor oil range petroleum hydrocarbons were not present in ' any of the groundwater samples at concentrations above the laboratory reporting limits • Deep well MW-105 contained 53 µg/l TPH-D ' • Wells MW-5 and MW-105 did not contain ethanol above the laboratory reporting limits Ethanol had previously been detected in well MW-105 at 58,000 µg/l The analysts for ethanol will be repeated for the September 2001 event ' • Wells MW-2 & 3 did not contain diesel contamination These wells did contain contamination in March 2001 • The lateral extent of the diesel groundwater plume is currently undefined due to the changes to groundwater direction • The vertical extent of the plume is intermittently defined by MW-105 r f