ARCHIVED REPORTS_XR0009516 - Laserfiche WebLink

Home Browse Search

' 3.0 GROUNDWATER MONITORING • 3.1 Groundwater Sampling Activities ' JJW Geosciences, Inc. (JJW) conducted groundwater monitoring and sampling activities on May 29, 2002. Prior to purging the wells and collecting groundwater samples, we measured ' and recorded the depth to static groundwater in the five wells. We present current groundwater gradient and flow directions in Table I. Following water depth measurements, we used a 12-volt DC pump to purge the groundwater monitoring wells until at least two or more ' of the readings for temperature, pH, conductivity, and oxidation-reduction potential (ORP) approximately stabilized or three well volumes were purged. Following well purging and recharge, we collected groundwater samples with polyethylene, well-dedicated disposal ' bailers and poured the collected groundwater into precleaned 40 milliliter glass vials and 250 milliliter amber glass jars. JJW experienced no ambient petroleum-like odors above the monitoring wells. Following collection, we immediately placed the water samples on ice in a ' cooler. Specific site conditions and sampling parameters can be found in the Well Sample Field Logs included in Appendix A. ' JJW transported the groundwater samples under chain-of-custody to Kiff Analytical (Certification No. 2236), a State of California certified analytical laboratory. The groundwater samples were analyzed for the following parameters. ' Total petroleum hydrocarbons as gasoline, TPH-g (EPA method 82606). The aromatic fuel components benzene, toluene, ethylbenzene, and xylenes (BTEX) ' (EPA method 8260B). Fuel oxygenates MTBE, DIPE, ETBE, TAME, tert-butanol, methanol, ethanol (EPA method 82606). ' 1,2 dichloroethane (1,2 DCA) and 1,2 dibromoethane (1,2 DBA) (EPA method 8260B). ' Cumulative groundwater analytical results are summarized in Table ll. The analytical laboratory data sheets can be found in Appendix B. 3.2 Groundwater Sample Laboratory Analytical Results ' Laboratory analyses indicated that the aromatic volatile hydrocarbons (BTEX) and total petroleum hydrocarbons as gasoline (TPH-g) were not detected above the method reporting ' limits in any of the five Monitor wells. Additionally, none of the seven oxygenates nor the lead scavengers 1,2 DCA and 1,2 DBA were detected above the method reporting limit in any of the five wells. ' See Table II for Cumulative Groundwater Analytical Results. The analytical laboratory data sheets can be found in Appendix B. 3.3 Groundwater Flow ©irection and Gradient ' The shallow groundwater was calculated to flow toward the north (N 9 E) with a groundwater gradient of approximately 0.0046 tuft. This is consistent with data collected from previous sampling events. ' 4 JJW GEOSCIENCES Inc.