ARCHIVED REPORTS_XR0006238 - Laserfiche WebLink

Home Browse Search

in 40-m1 VOA vials. Vials were labeled and preserved in an ice-filled cooler for storage and transport under appropriate chain-of-custody procedures Samples were sent to Pace Incorporated and analyzed for Total Petroleum Hydrocarbons as gasoline (TPH-g) by DHS-modified EPA Method 8015 and for benzene, toluene, ethylbenzene, and xylenes (BTEX) by EPA Method 8020 Field documentation logs are included as Appendix A 4. SUMMARY OF RESULTS On 30 December 1993, water levels in all wells on and off the site (with the exception of wells MW7, MW9, MW 11, and MW 12) were measured Measurements and groundwater ' elevations for 30 December are presented in boldface type in Table 1 with previous data The inferred direction of groundwater gradient is to the north-northeast, at a magnitude of 0 01 (Figure 3), which is consistent with previous data Groundwater elevations have increased an ' average of 0 65 feet since the previous quarter Also on 30 December, wells MW1, MW8, MW13, RWI—RW4, Pl, P2, V2, and V4 were purged and sampled The analytical results for the samples collected on 30 December are presented in boldface type in Table 1 with results of previous analyses The laboratory ' analytical report is included as Appendix B No petroleum hydrocarbons at concentrations equal to or greater than method detection lunits were found in the sample collected from well MW13 (farthest downgradient) Wells MW9, MW 1 I, and MW 12 were not accessible, as the lids could not be opened Concentrations of TPH-g in samples ranged from 390 pg/L in MW1 to 170,000 pg/L in V2 (Figure 1) Concentrations of benzene ranged from 12 lig/L in MW1 to 27,000 pg/L in V2 (Figure 1) Excluding the analytical results for the samples of groundwater collected from MW13, petroleum hydrocarbon concentrations were lowest in the samples collected from MW1, P1, and P2, located along the western boundary of the site The concentration of TPH-g in the sample collected from MW8, located adjacent to the Shell service station and upgradient of P1 and P2, was 50,000 pg/L Concentrations of petroleum hydrocarbons were generally consistent with previous sampling events, with the exception of P1 and P2 which had a significant increase LPH has not been detected in any well since October 1992 ' 5. WORK PROPOSED FOR NEXT QUARTER Water elevations in groundwater monitoring wells will be measured and groundwater samples collected in February 1994 The samples will be analyzed for petroleum hydrocarbons ' The soil vapor extraction and air sparging system will be in operation in February 1994 73942QI293 2 2 t