ARCHIVED REPORTS XR0010723 - Laserfiche WebLink

Home Browse Search

CALIFORNIA GEOPHYSICAL GROUP, INC. O Box 578341, Modesto, CA 95357 Tel- (209) 527-1247 October 25, 2003 Fax- (209) 527-4810 ' RECIEli'V,[ED w ' Public Health Services NOV 14 2003 San Joaquin County 304 East Weber Ave 3rd Floor ENVIRONMENT HEALTH ' Stockton, CA 95202 PERMIT/SERVICES RE Quarterly Report October 2003 Darpetro, Inc USA Service Station 749 E Charter Way Stockton, CA ' Site No 1060 This site was sampled on October 8, 2003 Sherwood Labs of Hilmar, California analyzed ' the samples, their reports are attached Table 1 lists the history of the water table depths and elevations at this site since January ' 26, 1990 Table 2 lists the hydraulic gradients and bearings and Tables 3 and 313 lists the analyses of the groundwater Table 5 lists the readings at the Vapor Extractor during operation Sampling protocols are included lie FINDINGS' The groundwater fell approximately 1 2 feet since the last quarterly monitoring event The ' gradient bearing is N 55 E The gradient is 0 0018 Ftlft See Table 1 and Figure 1 The wells were purged with a decontaminated pump and the measured field parameters stabilized at the end of the purging Water samples were taken with a contaminated bailer See Protocols Water samples were placed in appropriate glass containers with Teflon-lined seals f The groundwater in wells BM-1, BM-5, BM-6, BM-7, BM-9 and BM-11, were above California Drinking Water Standards for benzene Wells BM-9 and BM-7 and possibly BM-6 is related to the contamination entering from the Stations to the west See Table 3 ' and Figure 2 The sparging point is within the old tank pit See Figure 1 for the AS well See Table 5 for ' the vapor input The sparger is under repair and is not operating at this time The contamination from this site is TPH and chemicals related to gasoline, but there is no MtBE or other oxygenates related to the tanks on this property ' Dissolved oxygen levels were recorded this quarter at this site The levels were measured with a calibrated YSI model 51 B meter by placing the sensor 5 feet below the I ,