ARCHIVED REPORTS_XR0003097 - Laserfiche WebLink

Home Browse Search

3.3 Subsurface Conditions Soils encountered beneath the site consist primarily of sands and silts to approximately 86 5 feet below grade, the maximum depth explored Lean clay was encountered at a depth of approximately 75-82 feet below grade Four soil samples from MW-1 were submitted for laboratory analysis from depths of 40 5 feet, 50 5 feet, 55 5 feet, and 65 5 feet below grade Benzene was not detected at or above method detection ' limits in any of the samples Toluene was detected in the 40 5 foot sample [0 23 parts per million (ppm)], 55 5 foot sample (0 010 ppm), and the 65 5 foot sample (0 014 ppm) Ethylbenzene was detected in the 40 5 foot sample (0 33 ppm) Xylenes were detected in the 40 5 foot (58 ppm) and 55 5 foot (0 017 ppm) samples TPHG was detected in the 40 5 feet (2900 ppm) sample only Table 3 summarizes the laboratory results Appendix IV contains laboratory data sheets and chain-of-custody documentation ' Laboratory Y sample analysis of the water le did not detect benzene at or above method detection Iimits P Toluene was detected at 0 6 parts per billion (ppb), ethylbenzene at 6 8 ppb, xylenes at 31 ppb, and TPHG at 1600 ppb The analytical results are summarized to Table 4 Laboratory data sheets and chain-of-custody documentation are included in Appendix IV 1 4.0 CONCLUSIONS 4.1 Soil Laboratory results from tank removals and the initial subsurface investigation (Phase I) indicate up to 50 2 ppm total BTEX and 400 ppm TPHG remain in the former gasoline tank pit. The soil borings around the perimeter of the excavation determined that soil contamination is not laterally extensive Laboratory analyses of soil samples collected beneath the tank pit which formerly accommodated the 350-gallon waste oil tank contained low levels of TPHD (4.5 ppm) at approximately 7-feet below grade Low levels of polychlonnated biphenols (PCBs), cadmium, chromium, lead and zinc were also detected from soil collected during tank removal R-042992 TJL 6