ARCHIVED REPORTS_XR0005853 - Laserfiche WebLink

Home Browse Search

i 17 September 2004 AGE-NC Project No. 95-0137 ' Page 2 of 4 2.2. COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES Water samples were collected from the purged wells using new disposable plastic bailers after allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume.Each sample was transferred into three 40-milliliter(ml)EPA-approved volatile organic analysis(VOA)vials and into one 1-liter amber bottle. Samples were properly labeled, stored in a chilled container and ' transported under chain-of-custody to Cal Tech Environmental Laboratories (CTEL) a California Department of Health Services (DHS)-certified laboratory. Each sample was analyzed for: rytr -0;1 01 • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d) in tl °/ ' accordance with EPA Method 8015 Modified; and • BTEX compounds and the oxygenating fuel additives: methyl tertiary butyl ether(MTBE), ' tertiary butyl alcohol(TBA),di-isopropyl ether(DIPE),ethyl tertiary butyl ether(ETBE)and tertiary amyl methyl ether (TAME), 1,2-dibromoethane (EDB) and 1,2-dichloroethane ' (1,2-DCA) in accordance with EPA Method 8260B. r. 3.0. FINDINGS ' Ground water elevation, flow direction and gradient were determined from field data collected on 22 July 2004; the contaminant impact to ground water was quantified from the ground water laboratory data. 3.1. GROUND WATER GRADIENT AND FLOW DIRECTION ' Depths to ground water during the July 2004 monitoring event ranged from 25.89 to 26.90 feet below the well casing tops; the depth to ground water remained stable since the March 2004 ' monitoring event. The calculated ground water elevations ranged from 30.98 feet (MW-4) to 33.98 feet(MW-5),and ground water flow was inferred to be northwest at an approximate hydraulic gradient of 0.02 foot/foot at the former UST area(Figure 3). - 3.2. ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g, TPH-d and BTEX compounds were not detected in the ground water samples. The lead scavenger 1,2-DCA was detected-in samples from well MW-2 and MW-4 at concentrations of 9.8 micrograms per liter (}Lg/l) and 63 Rg/l, respectively. No additional contaminants of concern were detected in the analyzed samples. The analytical results are summarized in Tables 2 and 3. A copy ' Advanced GeoEnvironmental,Inc.