ARCHIVED REPORTS_XR0007370 CASE 2

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• A minimum of three casing volumes was purged from each monitor well before groundwater samples were taken I • Field readings were taken at approximately five-gallon intervals to monitor the pH, temperature, turbidity and conductivity of the extracted water (copies of the field sheets are included in Appendix B) • At the conclusion of each well's purging, groundwater samples were collected into laboratory-supplied 40-m1 VOA vials and one-liter amber glass sample bottles • The sample containers were properly labeled, placed into a cool ice chest and transported under strict chain-of-custody documentation to Severn Trent Laboratory (STL) in Pleasanton, California for analysis • The samples were analyzed by EPA method 8015M for diesel range petroleum hydrocarbons (TPH-diesel) and by EPA method 8021B for benzene, toluene, Iethyl benzene, and xylenes (BTEX) IANALYTICAL RESULTS AND FIELD OBSERVATIONS Laboratory analyses of the soil samples collected from the eight borings report Ivery low concentrations of TPH-diesel throughout each of the soil columns The highest concentration (78 mg/kg) was found at a depth of 5 feet bsg to BH-15 but the concentrations decreased dramatically beyond that depth The second highest • concentration (66 mg/kg) was found in a soil sample taken from BH-16 at a depth of 114 feet bsg, however, the concentrations above and below that depth were much lower The analyses of the samples from the other six borings reported concentrations ranging from I1 6 mg/kg to a single high of 28 0 mg/kg The laboratory results for BTEX analyses on the soil samples extracted from the eight borings were all non-detect (<0 0050 mg/kg) I The results of the laboratory analyses are presented in Table 1 A copy of the laboratory analytical reports and the chain-of-custody records are included in Appendix A The laboratory analyses of groundwater samples taken at the culmination of the two new well's developments report non-detect (<50 µg/L) for TPH-diesel Analyses for volatile petroleum products (BTEX) in the samples resulted in findings of very low, I nearly identical, concentrations in both wells In MW-07, the reported concentrations were 2 9 µg/L benzene, 11 µg/L toluene, 2 7 µg/L ethyl benzene and 14 pg/L xylenes In MW-08, the reported concentrations were 2 5 µg/L benzene, 11 µg/L toluene, 2 8 µg/l, I ethyl benzene and 16 µg/L xylenes The results of the laboratory analyses are presented in Table 4 Copies of the laboratory reports and chain-of-custody records are included in Appendix A INo free-phase liquid hydrocarbon Iayer or sheen was seen on the water tape or the pump equipment during the development or sampling of the groundwater monitoring wells, and all purged and sampled water lacked any discernable odor(see field sheets, Appendix B) I 4