ARCHIVED REPORTS_XR0008736 - Laserfiche WebLink

Home Browse Search

1 ' 5.6 Groundwater Monitoring and Sampling Groundwater gauging and sampling was performed by ATC on January 16, 2003 During this gauging ' event the depth to groundwater beneath the site ranged from 55 04 (MW-13) to 55 92 (MW-14) feet bgs No PSH was encountered in any of the 21 wells gauged during this event Based on the data collected during the most recent groundwater gauging event (January 16, 2002), the hydraulic gradient and flow direction were calculated This gradient and flow direction is based only on data collected from properly screened wells A hydraulic gradient of approximately 0 001 vertical feet to horizontal foot (ft/ft) ' trending towards the northwest was calculated Groundwater conditions as observed on January 16, 2003 are illustrated on Figure 9, Groundwater Summary Map (January 16, 2003) Analytical results for past and current groundwater sampling events are summarized in Tables 3 and 4 ATC will gauge,purge, and collect groundwater samples from all of the groundwater monitor wells in the network (MW-1 through MW 17), and vapor wells (VW-1 through VW-3) on a quarterly basis, as directed by the San Joaquin County Environmental Health Department Assurrung that phase-separated hydrocarbons (PSH) are not present in all wells, static water levels in each ' well not containing PSH will be measured, and a representative groundwater sample will be collected from the well in general accordance with ATC's Standard Operating Procedure - Groundwater Monitor ' Well Purging and Sampling which is included in Appendix. C Quarterly groundwater monitoring;i eport-_ will be prepared and submitted to the San Joaquin County Environmental Health Department The reports will summarize the quarterly groundwater elevation measurements, calculated groundwater gradient and flow direction and analytical results of the quarterly sampling 5 7 Analytical Testing ' Analyses of soil and groundwater samples was performed by ZymaX Envirotechnology(ZymaX), a State- certified laboratory Quality Assurance and Quality Control (QA/QC) procedures, sample preservation, apparatus required, and analyses performed will be per 1) A A C R9-14-601 through -617, 2) U S EPA Document EPA-600, "Methods for Chemical Analysis for Water and Wastes" dated July 1982, and 3) U S EPA document SW-846, 3rd Edition, "Test Methods for Evaluating Solid Waste Physical Chemical Methods", dated November 1986 Select soil and groundwater samples were analyzed for total petroleum hydrocarbons characterized as gasoline (TPHg), benzene, toluene, ethylbenzene, total xylenes (BTEX), methyl-tertiary-butyl ether (MTBE), tert-amyl methyl ether (TAME), tert-butyl alcohol (TBA), di-isopropyl ether (DIPE), and ethyl- tert-butyl ether (ETBE) in accordance with Environmental Protection Agency (EPA) Test Method 8260B All groundwater samples were additionally analyzed for 1,2-dichlorethane, and ethylene dibromide in accordance with EPA Test Method 8260B EZ 100966ASAR rpt ATC Associates Inc ' 11San Diego1EZ Serve11009661Reports1100966SAR001 rpt ATC Project No 43 25827 0026 10