ARCHIVED REPORTS XR0010663 - Laserfiche WebLink

Home Browse Search

1 CALIFORNIA GEOPHYSICAL GROUP, INC. O Box 578341, Modesto, CA 95357 Tel (209) 527-1247 November 22 , 1996 Fax (209) 527-4810 Public Health Services t ery ces San Joaquin County P.O. Box 388 Stockton, Ca 95201 RE: Quarterly Report October, 1996 Darpetro Service Station 749 E. Charter Way Stockton, Ca. Site # 1060 ' The site was sampled on October 28 , 1996 and the water samples were sent to Sherwood Labs of Hilmar, California, who forwarded them to Associated Laboratories. The water table measurements, ' sampling parameters and chain of custody are attached. Table 1 lists the water levels and depths to water, since January ' 26, 3990. Table 2 lists the hydraulic gradients and bearings and Table 3 list the chemical analyses taken each quarter. Also attached is a plot of the water table contours on October 28 , 1996. The water samples were obtained by using a clean pump. This was performed after the measured field parameters had stabilized ' during the purging with a pump. See protocols. Water samples were placed in appropriate glass containers with teflon-lined lids. Wells MW-1, 2 and 3 were not measured or sampled, authorized by Mr, Steve Sasson, the county regulator. ' FINDINGS The groundwater flow is to the Northeast at a gradient of 0.0021 Ft/Ft. The groundwater level has fallen about 0.8 feet, since the last quarterly reading. Figure 1 shows the water table elevations. Benzene contamination is present in all of the wells above the California Action Levels. Also the oxygen levels were measured using a YSI Model 51B oxygen level meter. The meter was calibrated the day before performing the testing. The oxygen level was measured 5 feet below the surface of the water table. The chemical MTBE was not tested for this quarter. It was tested for twice this year and no MTBE was found. Also the ferrous iron, nitrate and sulfate levels were tested for Page 1