ARCHIVED REPORTS_XR0005082 - Laserfiche WebLink

Home Browse Search

'• 01 October 2004 • AGE-NC Project No. 98-0520 tPage 2 of 4 After collection, the samples were properly labeled, placed in a chilled container and transported '. under chain of custody to Cal Tech Environmental Laboratories (CTEL), a State of California Department of Health Services(DHS)-certified analytical laboratory,for analysis.The samples were analyzed for: Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA Method 8015M; and • Benzene, toluene, ethylbenzene and xylenes (BTEX) and fuel additives including methyl tertiary-butyl ether,(MTBE), tertiary butanol (TBA), di-isopropyl ether (DIPE), ethyl tert- �' butyl ether (ETBE), tert-arnyl methyl ether (TAME), 1,2-dichloroethane (1,2-DCA) and 1,2-dibromoethane (EDB) in accordance with EPAMethod 8260B. 3.0. FINDINGS ' Ground water elevation and flow direction were determined from field data collected on 17 June 2004. Hydrocarbon-impact to ground water was quantified from laboratory analysis of the ground water samples. ' 3.1. GROUND WATER ELEVATION AND.GRADIENT The elevation of ground water in each well was calculated by subtracting the depth to ground water r from the surveyed casing elevations (Table 1). Depths to ground water ranged from 24.15 feet (MW-7) to 25.34 feet (MW-6) below the tops of the well casings (btoc). Ground water elevations at the site, not including MW-6, averaged approximately 11.77 feet above mean sea level,(MSL), showing an elevation decrease of approximately 2.23 feet since the last monitoring event. The ground water flow direction was determined using ground water elevation data from water table wells MW-1 through MW-5 and MW-7 through MW-10; elevation data from well MW-6 was not, utilized because well MW-6 is a deep-screened well. The shape of the water table at the time of the June 2004 monitoring event was in the form of a northwest-plunging trough. Net flow of ground ' water at the site was determined to be to the northwest under an average gradient of approximately 0.002 foot/foot. Figure 3 illustrates the contoured ground water elevations as measured on 17 June 2004. 1 ' Advanced GeoEnvirontnental,Inc.