ARCHIVED REPORTS_XR0010586 - Laserfiche WebLink

Home Browse Search

i 11 June 2002 AGE-NC Project No 96-0249 Page 5 of 6 I wells MW-1, MW-2 and MW-3 (screened between 5 and 25 feet bsg) suggest that these wells may be screened within or near a "core area" of a dissolved petroleum hydrocarbon plume However, the area of greatest dissolved petroleum hydrocarbon-impact was encountered in the samples from wells MW-3 and MW-6 (Figure 4) Lower petroleum hydrocarbon concentrations were detected from intermediate well MW-1 which may indicate a separate plume of dissolved petroleum hydrocarbons in the area of MW-6 I • The distribution of MTBE concentrations detected in Three B's Truck Plaza wells MW-1, MW-2, MW-4, MW-6 and Flag City Chevron wells MW-7 suggest the possibility of two separate dissolved MTBE-plumes (Figure 6) • The distribution of TPH-d concentrations detected in Three B's Truck Plaza wells MW-1, MW-2, MW-3, MW-6 and Flag City Chevron wells MW-12A and MW-13A suggest the possibility of two separate dissolved TPH-d-plumes (Figure 5) • Laboratory results of grab water samples collected from DW-1 indicate that there is currently no petroleum-impact to the Three B's Truck Plaza domestic drinking water well (Table 4), however, a down-hole video probe of DW-1 in November 2001 showed that the well casing from DW-1 extends from surface grade to 83 feet bsg and is open bore-hole from 83 to 98 I! feet bsg Based on grab water samples collected at the site during the cone penetrometer testing (CPT) site investigation in November 2001 (Cone Penetrometer Testing Site Investigation -Fourth Quarter 2001, dated 15 March 2002), substantial petroleum-impacted Iground water was detected at sampled depth intervals between first water and 110 feet bsg I5.0. RECOMMENDATIONS IBased upon data collected during March 2002, AGE recommends 1 Continued quarterly ground water monitoring at wells MW-1 through MW-6, the next Iquarterly ground water monitoring event is tentatively scheduled for June 2002 2 Continued coordination of quarterly ground water monitoring events with Flag City Chevron A Feasibility Studies and Monitoring Well Installation Work Plan was submitted to the SJCEHD on 24 May 2002, the scope of work includes installation of one ground water extraction well, two ground water monitoring wells, one ozone sparge well, six multi-levelground water monitoring wells, performance of a 24-hour ground water aquifer pumping test and performance of a 4-week I ozone sparging pilot test Upon approval by the SJCEHD and pre-approval by the UST Cleanup Fund, AGE will schedule field work with the SJCEHD s Advanced GeoEnvironmentul,Inc I