ARCHIVED REPORTS XR0010484 - Laserfiche WebLink

Home Browse Search

CALIFORNIA GEOPHYSICAL GROUP, INC. P.O. Box 691, Poway, CA 92074 Tel: (619) 486-1323 FAX: (619) 4 84 6 February 24, 1993 717 Public Health Services San Joaquin County P. O. Box 2009 MAR 11 1993 Stockton, Ca 95307HEALTH ENVIRONY11 PERMIT/SERVICES RE: Quarterly Report January 1993 Darpetro Service Station 749 E. Charter Way Stockton, Ca. Site # 1060 The site was sampled on January 29 1993 and the laboratory analyses of the water samples were done by Sherwood Labs of Hilmar, California. The water table measurements, sampling parameters and chain of custody are attached. Table I lists the history of the water analyses taken at the site since Jan. 26, 1990. Table II is the history of the water table measurements, and Table III list the history of Hydraulic Gradients. Attached is one water table elevation plot showing the approximate groundwater gradient. The water samples were obtained by using a pre-cleaned teflon bailer and new section of rope. This was performed after the measured field parameters had stabilized during the purging operation. See protocols. Water samples were placed in appropriate glass containers with teflon-lined lids. FINDINGS The water table elevation has risen slightly about 0. 5 feet. However, the bearing of the hydraulic gradient has shifted to the north 40 degrees and is now N30E. The slope of the gradient remains high. The contamination in wells 4 and 5 has increased dramatically. There is now 3 inches of floating product in well 5. This is the first time this has been noted. We also found the looking cap on the well had been broken off. We had to lower the top of the casing to put a new cap on, and we resurveyed the tops of the casings. The new elevations are now listed in Table II. It is our belief someone maliciously poured raw gasoline down this well sometime in the last quarter.