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BUAVEnvironmental Management Inc U-Haul#709-50 002-70950-02 Semi-Annual Report 12/14/00 .2 2 r ndwater am le An l ne 2 0 The groundwater samples were analyzed for TPHg according the CA/LUFT method, and benzene, toluene, ethylbenzene, total xylenes (BTEX), methyl tert-butyl ether (MTBE), tert-Butyl Alcohol (TBA), ' Dilsopropyl Ether (DIPS), Ethyl tert-Butyl Ether (ETBE), and tert-Amyl Methyl Ether (TAME) according to EPA Method 8260 Groundwater samples collected from monitor wells MW-2 and MW-213 were additionally analyzed for TPH as Diesel (TPHd) using the CA/LUFT method and for halogenated hydrocarbons using EPA Method 8260 The EPA Method 8260 is comparable to the EPA Method 8010 analysis with exception to the equipment used for the analysis The EPA Method 8260 includes the same ' analytes, however, it is run on a more sensitive machine ZGroundwater Analytical Results-Jung 2000 Laboratory analytical results of the June 2000 groundwater sampling event indicate that groundwater ' beneath the site contains hydrocarbons at variable concentrations A summary of analytical results for the June 2000 sampling event is presented in Table 2 A copy of the corresponding laboratory analytical ' report and chain-of-custody documentation is provided in Appendix C Reviewing the results by sample group (i a the upper casings, middle casings and lower casings) reveal inconsistent results Analytical results of groundwater samples collected from the well casings screened across the groundwater interface (casings "A" and MW-413) reveal the highest concentrations of hydrocarbons in groundwater from wells MW-3A and MW-4B The concentrations of hydrocarbons in groundwater from MW-3A (170,000 gg/L TPHg and 32,000 l.ig/L benzene) suggest the source area of hydrocarbons was near MW-3A The extent of hydrocarbons at the groundwater surface was defined by analytical results of groundwater samples collected from monitor wells MW-9A to the south, MW-6A to the west, MW-2A to the northwest, and MW-5A to the north These groundwater samples did not contain detectable concentrations of TPHg or benzene The hydrocarbon concentration map for wells screened across the groundwater interface (Figure 4) shows a "bulls-eye" pattern centered at the former dispenser islands The eastern extent of hydrocarbons in groundwater remains undefined Analytical results of groundwater samples collected from the wells screened at depths of approximately 52 to 77 feet bgs (middle "B" casings) revealed the highest concentrations of hydrocarbons in groundwater from wells MW-313 and MW-613 The concentration of hydrocarbons in groundwater from MW-3B (180,000 gg/L TPHg and 35,000 �tg/L benzene) were similar to the results from MW-3A • 9