ARCHIVED REPORTS XR0001939 - Laserfiche WebLink

Home Browse Search

4 i 1 J� ' _ 1 25 January 2001 AGE-NC Project No 97-012 ' Page 2 of 4 top of the water column to remove water trapped wlthm the unscreened interval of the well casings Temperature,pH and conductivity of purged water were measured at regular intervals during purging using a Hydac water analyzer The recorded field data and logs are included In Appyendix A purged water was stored on-site in 55-gallon DOT-approved drums pending laboratory analysis - ' 22 COLLECTION OF GROUND WATER SAMPLES 1 The depth to water was re-measured following purging to assure a minimum of 80% recharge pnor to sampling Water samples were retrieved from each purged well using new disposable bailers To sample the domestic wells, a sampling port was opened,at the well head and samples were collected ' from the sampling port while the pump was operating to obtain fresh water samples Each sample ` r was transferred into three laboratory-supplied 40-m1 EPA-approved VOA vials'contaln>ng 0 5 ml of 18% hydrochloric acid as a sample preservative and Into one 1-liter amber bottles without preservative The samples were labeled,placed In a chilled container and transported under chain-of- custody to McCampbell Analytical Inc (MAI) In Pacheco, a California DepartH ealth Services (DHS)-certified analytical laboratory The samples were analyzed for ment of lie • Total petroleum hydrocarbons quantified as gasoline (TPH-g) and diesel (Tl'H-d) In accordance with EPA Methods 5030 and 8015m, ' - Volatile aromatic hydrocarbons - benzene, toluene, eth lbenzene and total xylen'es ) with methyl tertiary-butyl ether(MTBE) In accordance with EPA Method 8020/602, and Volatile organics and fuel oxygenates - MTBE, di-Isopropyl ether (RIPE), ethyl,tert-butyl y I { � ether (ETBE),,tent-amyl methyl ether (TAME) and tert-butanol (TBA) In accordance with EPA Method 8260 modified i 3•0• FINDINGS , Ground water elevations were determined by subtracting the measured depths-to-water from the f surveyed casing elevations (Table 1) Ground water flow direction was determined by contouring the water elevations on a scaled site plan (Figure 4) Hydrocarbon-Impact to ground water 'was assessed by laboratory analysis and field observations 3 1 GROUND WATER ELEVATION AND GRADIENT T Ground water elevation increased an average of 2 53 feet at the site since the 28 Se tem e monitoring event Ground water flow direction was Inferred to be p b r 2400 northeasterly The flow direction i t Advanced GeoEnvironmental,Ine '