ARCHIVED REPORTS_XR0005430 - Laserfiche WebLink

Home Browse Search

' 09 March I998 • AGE-NC Project No 95-0173 ' Page 2 of 5 ' 2 2 GROUND WATER SAMPLING The ground water levels in the monitoring wells were allowed to recover for a minimum of one hour prior to sample collection Ground water samples were collected utilizing disposable polyethylene bailers and new nylon rope Sufficient ground water sample was collected from each well to fill three 40-m1 EPA-approved VOA vials containing 0 5 ml 18%hydrochloric acid as a preservative for the ' samples and a one liter amber bottle Care was taken to ensure that visible air bubbles were not present In the VOA vials after filling and capping Ground water sample containers were labeled with the well designation, date, time, and sampler's initials I 23 LABORATORY ANALYSIS OF GROUND WATER SAMPLES Each ground water sample was logged on a chain-of-custody form,placed in a chilled container and transported to a California state-certified laboratory for analysis in accordance with EPA method 8015M for total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, respectively), In accordance with EPA method 8020 for volatile aromatics (benzene, toluene, ethyl • benzene and xylene BTE&X)with methyl-tertiary butyl ether(MTBE), and In accordance with EPA method 8260 for volatile organics (including oxygenates) The laboratory report (Castle Analytical Laboratory Reference No 1405 and McCampbell Analytical Inc Lab I D 84929 to 84940) and chain-of-custody forms are presented in Appendix B 3 0. FINDINGS 3 I RELATIVE GROUND WATER ELEVATION AND GRADIENT EThe depths to ground water in the monitoring wells were measured between 30 88 and 33 25 feet below the top of the well casings Between October 1997 and January 1998, depth to ground water decreased an average 1 08 feet at the site During the January 1998 ground water monitoring event, the gradient was calculated to be 0 003 ft/ft, or approximately 17 feet per mile (Figure 3) Ground water monitoring data collected In the area of the monitoring wells suggests that the ground water flow direction was generally toward the northeast The ground water elevation data for the monitoring wells during the January 1998 ground water monitoring event is depicted In Figure 3 • Advanced CcoEn,tronmental,Inc