ARCHIVED REPORTS XR0006451 - Laserfiche WebLink

Home Browse Search

17 April 2000 AGE-NC Project No. 95-0197 ' Page 2 of 4 ' 2.2. GROUNDWATER SAMPLING Following well purging,ground water levels in monitoring wells MW-1,MW-2, MW 3, and MW-4 ' achieved a minimum of 80 percent recharge prior to sample collection. Ground water samples were collected from the purged wells utilizing new, disposable polyethylene bailers, 1-liter amber bottles and three EPA-approved 40-m1 VOA vials containing 0.5 ml 18% hydrochloric acid as a sample ' preservative. Care was taken to ensure that visible air bubbles were not present in the vials after filling and capping. Ground water sample containers were labeled with the well designation, date, time, and sampler's initials. 2.3. 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 Department of Health Services (DHS)-certified laboratory for analysis for: Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, ' respectively)by EPA Method 8015M, Volatile aromatic compounds (benzene, toluene, ethyl benzene and xylene: BTEX) with methyl-tertiary butyl ether (MTBE)by EPA Method 8020, and Tertiary butanol (TBA),'di-isopropyl ether (DIPE), ethyl tert butyl ether(ETBE), tert amyl methyl ether(TAME) and MTBE by EPA Method 8260M. ' 3.0. FINDINGS Ground water elevation, flow direction,.and gradient were determined from field data collected on ' 27 March 2400; the contaminant impact to ground water was assessed from the laboratory data. ' 3.1. GROUND. WATER ELEVATION AND GRADIENT The depths to ground water from wells MW-I., MW-2, MW-3, and MW-4 were measured between ' 13.78 and 14.37 feet below the tops of well casings. Ground water elevations were calculated to lie between 8.97 feet and 9.13 feet below mean sea level; ground water elevations, as measured on 27 March 2000 are depicted in Figure 3. Ground water elevation at the site increased an average 2.44 feet between the October 1999 and the March 2000 ground water monitoring events. The general ground water gradient at the site was calculated to be approximately 0.002 fl/ft or approximately 10 Advanced GeoEnvironmental,Inc.