ARCHIVED REPORTS_XR0004199 - Laserfiche WebLink

Home Browse Search

I 15 December 2004 . AGE-NC Project No 99-0624 ' Page 2 of 4 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES Water samples were collected from each purged well using a Watera hydrolift pump and dedicated ' - tubing after allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume Each water sample was transferred into three 40-m1 volatile organic analysis(VOA)vials containing 0 5 ml 18%hydrochloric acid as a sample preservative 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-certified analytical laboratory The samples were analyzed for ' Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA Methods 8015M, ' a Benzene, toluene, ethylbenzene and xylenes (BTEX) in accordance with EPA Method 8260B, and r ' 0 Fuel additives di-isopropyl ether(DIPE), ethyl tertiary-butyl ether(ETBE),methyl tertiary- butyl ether (MTBE), tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), 1,2-dichloroethane (1,2-DCA) and ethylene dibromzde (EDB) In accordance with EPA lie Method 8260B ' 3.0 FINDINGS ' Ground water elevation, flow direction, and gradient were determined from field data The contaminant Impact to ground water was quantified by the laboratory analytical data ' 3 1 GROUND WATER GRADIENT AND DIRECTION ' At the time of the August 2004 sampling event, depths to ground water ranged from 57 20 feet to 58 22 feet below the tops of the well casings (toc) Ground water elevations at the site ranged from 18 79 feet below mean sea level (MSL) in well MW-4 to 19 23 feet below MSL in well MW-5 ' (Table 2) During this monitoring event,the groundwater levels in wells MW-1 through MW-6 were at least twelve feet below the tops of the well screens,indicating that the wells are screened properly ' to yield representative shallow ground water-samples The ground water elevation at the site decreased approximately 4 27 feet between the May 2004 and August 2004 monitoring events ' The ground water was inferred to be flowing towards the south-southeast The average ground water gradient was determined to be approximately 0 003 f1/ft Figure 3 illustrates the contoured ground water elevations as measured on 12 August 2004 ' Advanced GcoEnvironmental,Inc I