FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

DICK LELAND R& L BUSINESS MANAGEMENT (FORMERLY STOCKTON PLATING) 3826 GLENEAGLES DRIVE STOCKTON CA 95219-1832 RE: STOCKTON PLATING ! ' SITE CODE: 1986 632 S. ELDORADO STREET STOCKTON CA ' San Joaquin County Environmental Health Department (EHD) is the lead agency providing the oversight of the investigation and cleanup of releases from underground storage tanks (UST's) within San Joaquin County. EHD has a contract with California State Water Resources Control Board to conduct an underground storage tank program. The above referenced site was placed in the EHD Local Oversight Program (LOP) in April 1991. EHD has reviewed the Final Remediation Plan prepared by Advanced GeoEnvironmental (AGE) dated April 23, 2002 and has the following comments. Two USTs were removed from the above referenced site: one 1,000-gallon leaded gasoline UST in 1986 and one 2,000-gallon unleaded gasoline UST in 1990. The soil results from the 1990 UST removal evidenced high concentrations of gasoline from an unauthorized release and additional assessment and remediation were required. To date, several soil borings, eight groundwater monitoring wells (MWS), four vapor extraction wells (VWs), and two groundwater extraction wells (EWs) have been installed. Numerous soil probe borings were completed to collected soil vapor samples for analyses. The MWs and borings have defined the vertical and lateral extent of soil and groundwater contamination. In 1995, a soil vapor extraction test was completed using the 4 VWs. The vertical extent of contamination in the source had not been defined during the early 1990s, but has since been delineated with the installation of MW-6 in November 1998. At that time static water was 40 feet below ground surface (bgs). The static water level at this site was as deep as 45 feet bgs in the early 1990s when the initial vapor extraction tests were performed, but has risen to 25 feet bgs. Due to the rise in groundwater, AGE believes that the sustained increase of groundwater elevation has significantly decreased the potential effectiveness of air sparging in conjunction with soil vapor extraction as a stand alone treatment method. In 2001, AGE conducted a groundwater extraction pilot test using two EWs. AGE prepared a Groundwater Extraction Pilot Test Report dated January 31, 2002. The report stated that this method is feasible for corrective action. The constant pump rate of 5 gallons per minute was interpreted as being adequate to control further migration of contaminants downgradient from the source. The FRP has selected groundwater pump and treat in conjunction with soil vapor extraction. Four additional EWs are proposed to increase the capture zone and increase