Laserfiche WebLink
Aqua Terra Technologies <br /> CLOSURE REPORT-FORMER TANK CAR SITE-CROSSTOWN <br /> FREEWAY AND SOUTHERN PACIFIC RAILROAD INTERSECTION <br /> INTRODUCTION <br /> The site located at the intersection of the Crosstown Freeway <br /> and Southern Pacific Railroad was the former location of an <br /> underground fuel storage tanker car which was excavated under <br /> the supervision and instructions of Caltrans. At the time of <br /> the excavation, contaminated soil was also excavated and <br /> transported to Kettleman Hills, a Class I disposal site. The <br /> Regional Water Quality Control Board requested, upon <br /> reviewing the initial excavation procedures, that a <br /> groundwater monitoring well be installed in the center of the <br /> former tank location, that soil samples be collected at five <br /> foot intervals to groundwater and that a groundwater sample <br /> be collected. A four inch PVC groundwater monitoring well <br /> was subsequently installed by Aqua Terra. Soil samples were <br /> collected every five feet and a groundwater sample was <br /> collected upon completion of the well installation. The soil <br /> and water samples collected were analyzed for total petroleum <br /> hydrocarbons, benzene, xylene and toluene. A summary of the <br /> well installation, sample collection, analytical results and <br /> our recommendations appear in our report entitled, <br /> "Groundwater Contamination Assessment-Former Underground <br /> Storage Tank Site, Stockton, CA. " , dated June 2 , 1986. <br /> SCOPE OF WORK <br /> On June 27 , 1986, Caltrans requested that Aqua Terra proceed <br /> with their recommendations which appeared in the above cited <br /> report. Caltrans received approval from the Regional Water <br /> Quality Control Board and San Joaquin County Department of <br /> Environmental Health to proceed with remediation of the site, <br /> as recommended. <br /> The recommendations included remediating through excavation, <br /> the source contamination or the highest concentration of <br /> total petroleum hydrocarbons observed at a depth of <br /> approximately 14 feet. The groundwater sample indicated that <br /> no contamination was present in the groundwater at this time, <br /> therefore the County agreed to allow for the permanent <br /> closure of the well. <br /> The extent of contamination to be removed would be a field <br /> decision, however, the above agencies agreed that excavation <br /> could be terminated at 19-20 feet, providing that the <br /> majority of detectable hydrocarbons in the soil would have <br /> been removed by this depth. <br /> I <br />