ARCHIVED REPORTS_XR0004988 - Laserfiche WebLink

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CVAV D C I A T E S I N C SAMPLING ACTIVITIES On March 3, 2003, ATC personnel collected groundwater samples from monitoring wells MW1, MW3 through MW10, piezometers AS-1(d), PZ-la(d) and PZ-1b(d), and the on-site groundwater supply well DW A groundwater sample was not collected from well MW2 because of the presence of free product in the well The locations of the wells are shown on Figure 2 Prior to collection of groundwater samples, the depth to water, pH, electrical conductivity, and temperature were measured in the monitoring wells and recorded A minimum of three well casing volumes were purged from each monitoring well prior to sampling The wells were allowed to recover and samples were collected from each well using dedicated disposable bailers After the groundwater samples were collected, dissolved oxygen was measured in each well The groundwater samples collected from each well were submitted to State-certified Argon Laboratories Inc (ELAP Cert No 2359) in Ceres, California for chemical analysis of TPHg utilizing EPA method 8015 modified, benzene, toluene, ethylbenzene, and xylenes (BTEX) utilizing EPA method 8020, and methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE) di-isopropyl ether (DIPE), tertiary amyl ether (TAME), tertiary butyl ether (TBA), 1,2- dichloroethane (1,2-DCA), and 1,2-dibromoethane (EDB) utilizing EPA method 8260 Groundwater well purge and sample logs are contained in Attachment 1 • ANALYTICAL RESULTS Groundwater samples collected from wells MW1, MW3, MW6 and piezometers AS-1(d), PZ- la(d), and PZ-lb(d) contained the highest concentration of T d BTEX Groundwater samples collected from wells MW4, MW7, MWO'31 s at�l also contained detectable concentrations of, TPHg and BTEX constituents Detectable concentrations of TPHg ranged from 440,000` arts per billion (ppb) in piezometer PZ-la(d) to 180 ppb in well MW10 Detectable concentrations of benzene ranged from 50,000 ppb in piezometer PZ-la(d) to 4 5 ppb in well MW4 The groundwater sample collected from wells MW5 and MW9 contained no detectable concentrations of TPHg or BTEX -Ground ter samples collected from wells MW1, MW3 through MW 10 and piezometers AS-1(d1 a(d), and PZ-1 b(d) contained no detectable concentrations of oxygenate fuel additives although many of the reporting limits were elevated due to dilution The groundwater sample collected from on-site supply well DW labeled as influent water contained detectable concentrations of TPHg and BTEX, but contained no detectable concentrations of oxygenate fuel additives Analytical results of groundwater samples are summarized in Table 2 Laboratory data sheets and chain-of-custody documentation are contained in Attachment 2 GROUNDWATER FLOW DIRECTION Water level measurements were collected from wells MW1 through MW10 and piezometers AS- ILS AS-1(d), PZ-la(d), and PZ-lb(d) on March 3, 2003 Water levels in the shallow aquifer ranged from 65 44 to 67 20 feet below the tops of the well casing elevations, representing an average increase S\EnviromentaRI6393aEPORTSIIgr-2003 doe 3