Laserfiche WebLink
SOIL AND GROUNDWATER INVESTIGATION <br /> 7759 S. AIRPORT WAY <br /> STOCKTON, CALIFORNIA <br />' 1.0 INTRODUCTION <br /> This report presents the results of a soil and groundwater investigation conducted by ROY F <br />' WESTON, INC (WESTON®) for the San Joaquin County Mosquito and Vector Control Distnct <br /> facility at 7759 S Airport Way in Stockton, California (see Figure 1) The purpose of the <br /> investigation was to generate additional data to assist the San Joaquin County Public Health <br />' Services Environmental Health Division (EHD) in considering site closure certification <br /> 1.1 Background <br />' In March 1987, the SJCMVCD removed several underground storage tanks from the Stockton <br /> service yard As specifically related to this investigation, two 8,000 gallon underground storage <br />' tanks which had previously held light spray oils were removed trom an area east of the shop <br /> building as shown on the plot pian map presented in Figure 2 Soil samples taken from below <br /> the tanks indicated extractable petroleum hydrocarbons were present in the soil in concentrations <br />' up to 770 mg/Kg A remedial excavation was completed in April 1987 to an approximate depth <br /> of 27 feet below grade to remove impacted soils During the excavation, some samples taken <br /> for control purposes contained up to 5500 mg/Kg of extractable hydrocarbons Two <br /> confirmation samples were taken at the completion of the excavation from 20 and 27 feet below <br /> grade and a water sample was collected from a nearby water supply well to monitor groundwater <br /> conditions near the excavation The results of the analyses of these samples are as follows <br />' TABLE I <br /> Excavation Confirmation Sample Results <br />' Soil Samples (m�/Kg) Water Sample (mg/L) <br /> Analytical Parameter <br />' 20 feet 27 tact Water Well <br /> Benzene NDo, ND,, NDo oos <br />' Toluene NDo, ND,, ND,w, <br /> Xylene NDo, ND,, NDa w5 <br />' Other Volatile Hydrocarbons ND,o ND,0 ND002 <br /> Total Extractable Hydrocarbons ND5, 12 ND,5 <br />' ND = NondeteL table at the level of detection shown in subscript <br /> As shown in the table, only a low concentration of total extractable petroleum hydrocarbons was <br /> found in the soil sample taken at 27 feet below grade in the northwest corner of the excavation <br /> area No volatile petroleum hydrocarbon components were found in any of the soil samples <br /> taken during the project and all analytical parameters were nondetectable in the water supply <br /> well sample <br />' ST11W'rsVvrn1vcn1 %T-K 1 ionsroa <br />