Laserfiche WebLink
2.5.2 Groundwater Contamination <br /> Both gasoline and diesel contamination were detected in the initial sample collected from <br /> MW-1 in June of 1992 (260 ppb and 310 ppb, respectively). Only gasoline was detected in <br /> the sample collected in November of 1992. <br /> Benzene has <br /> been detected in 1 samples from MW-1 and MW-4. Toluene was detected only <br /> contamination has been detected in samples in the mural sample from MW-1. No con les from p <br /> MW-2, MW-3 or MW-5. In the November 1993 Quarterly Report, GeoAudit recommended <br /> ' that representatives of the Bank of Stockton, PHS/EHD, and GeoAudit meet to discuss the <br /> necessity for further work at this site. Until this meeting is held, GeoAudit continues to <br /> ' perform quarterly monitoring. <br /> 3.0 PROCEDURES <br /> 31 Monitoring Well Purge Procedures <br /> On February 9 1994, a Solinst water level meter was used to measure the depth th to <br /> groundwater in the five monitoring wells. After water levels were measured, a 2-stage purge <br /> ' pump was used to purge approximately 7 to 9 gallons of water from monitoring wells MW-1, <br /> MW-4 and MW-5. Temperature, pH and conductivity were measured at one-gallon intervals <br /> and recorded (Table 1). The purge water was placed in DOT-approved drums and stored <br /> on-site. <br /> 3.2 Groundwater Sample Collection <br /> Water samples were collected from MW-1, MW-4, and MW-5 using new disposable plastic <br /> bailers. Three 40-m1 EPA vials and one Miter amber bottle of water were collected from <br /> ' each well and transported in a chilled container to WEST Laboratories in Davis. Each <br /> sample was analyzed for TPH as gasoline and diesel, and BTE&X in accordance with EPA <br /> methods 8015m and 602. <br /> t4.0 FINDINGS <br /> 4.1 Groundwater Elevation <br /> ' The relative groundwater elevations for the monitoring wells were calculated by subtracting <br /> the water depth from the casing elevation (Table 2). Comparison of the October and <br /> February measurements indicates that water levels have risen approximately 2 feet since <br /> ' October. This rise in water levels follows the normal seasonal variation. <br /> Wea..L AO i2 9,V-1,0 5 <br /> ' Woeen LA QR3(l-941-1.10 <br />