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1992 Third Quarter Groundwater Monitoring Rc,port Request for Site Closure Franzia Brothers Winery, Ripon CA August 27 1997 W0190 01 (Attachment 1) Well purge logs are included in Attachment 2 Laboratory Analysis Groundwater samples were analyzed for benzene, toluene, ethylbenzene, and xylenes (BTEX), and total petroleum hydrocarbons as gasoline (TPHG) utilizing EPA methods 8020 and 503018015, respectively Laboratory analysis indicated no constituents at or above method detection limits in the samples collected from wells MW-1, MW-2, and MW-3 The analytical results are summarized in Table 2, the laboratory reports, QA/QC data, and chain-of-custody documentation are presented in Attachment 3 Request for Site Closure The Wine Group, Ltd (Franzia Brothers Winery) has fulfilled the County's request for the installation of two monitoring wells on-site (San Joaquin County correspondence dated April 9, 1991) The purposes of the additional wells cited by the County were 1) to determine the groundwater gradient, and 2) to determine the extent of groundwater impaction A review of groundwater gradient maps prepared by the San Joaquin County Flood Control District (SJCFCD) for the period Fall 1975 through Fall 1991 show the direction of groundwater movement in the subject area to be consistently to the north Depth to water measurements were approximately 40-50 feet below grade, except in Fall 1975 and Spring 1986 where the water table rose to 30-40 feet Monitoring well MWA was located in the downgradient direction of the highest soil contamination Well MWA contained detectable Ievels of toluene (0 85 ppb), ethylbenzene (0 63 ppb), xylenes (1 8 ppb), and TPHG (66 ppb) in September 1990, however, this sampling event occurred shortly after well installation and the detected constituents are most likely a result of drilling activity Well MW-1 contained xylenes (0 6 ppb) in February 1991, Just above the method detection limit (0 5 ppb) which may have been a result of sampling or laboratory error Laboratory results for October 1990 and May 1991 indicated nondetectable concentrations of the analytes No gasoline hydrocarbons or constituents were detected in the second and third quarter 1992 sampling events of wells MW-1, MW-2, and MW-3 It is our opinion that the direction of groundwater movement has been adequately defined by the SJCFCD and that our 1992 second and third quarter monitoring data confirm this The historical analytical data indicate that the groundwater impact beneath the site is minimal Because the site has been capped since the excavation and removal of the source material, RESNA feels that further sampling events are not warranted Further work at this site cannot prove to be beneficial due to the additional costs incurred by The Wine Group, Ltd , and the • QRTERLYIQR082092 rNt 2