ARCHIVED REPORTS_XR0004639 - Laserfiche WebLink

Home Browse Search

• 29 April 2005 AGE-NC Protect No 98-0497 Page 2 of 4 ' 2 2 GROUND WATER SAMPLE COLLECTION Prior to the collection of ground water samples, the depth to ground water was re-measured in each ' monitoring well to ensure that a minimum 80% of the initial water volume had recharged Water samples were collected from each well using a clean, disposable plastic bailer The water was transferred into one 1-liter amber bottle and three 40-milliliter(ml)volatile organic analysis(VOA) vials containing 0 5 ml 18% hydrochloric acid solution as a sample preservative After collection, the samples were labeled and placed in a chilled container for transport under chain of custody to Cal Tech Environmental Laboratories(CTEL),a California Department of Health Services(DHS)- certified DHS)- certifed analytical laboratory in Paramount, California The samples were analyzed for • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, ' respectively) in accordance with EPA Method 8015M, and • Benzene, toluene, ethylbenzene, and total xylenes (BTEX) and methyl tertiary-butyl ether ' (MTBE)in accordance with EPA Method 8021 . 3.0. FINDINGS ' Ground water elevation and flow direction were inferred from field data Hydrocarbon-impact to ground water was assessed by laboratory analysis of the ground water samples 3 1 GROUND WATER ELEVATION AND GRADIENT ' At the time of the March 2005 sampling event,depths to ground water at the site ranged from 64 85 feet(MW-5)to 66 03 feet(MW-4)below the tops of the well casings Ground water elevation at the site averaged approximately 40 58 feet below mean sea level(MSL),indicating an average increase in ground water elevations of 2 46 feet since the last monitoring event in November 2004 Ground water elevation data is included in Table 1 ' Ground water flow direction was calculated from the ground water elevation data The ground water flow was inferred to be flowing east-southeast at the northern edge of the former UST area and flowing southeast across the southern portion of the former UST area in the shape of a trough,under ' hydraulic gradients ranging from approximately 0 0006 ft/ft to 0 0013 ft/ft Figure 3 illustrates the contoured ground water elevations as measured on 15 March 2005 1 ' Advanced GeoEnnronmental,Inc