Laserfiche WebLink
Manteca Unified School District <br /> Subsurface Soil &Groundwater Invgation <br /> located within a 2000-foot radius will be conducted and well details, if available, <br /> obtained. <br /> 1.1 Site Description and History <br /> Previous studies (Kleinfelder, November 1998) report that on March 18, 1997 a <br /> 250-gallon underground storage tank (UST) was removed from an area adjacent <br /> to a Manteca Unified School District, Agricultural Shop Building. Reportedly, <br /> eight yards of soil were excavated from the tank cavity and stockpiled onsite. Two <br /> soil samples were collected by GeoAnalytical Laboratories of Modesto, California <br /> and analyzed for Benzene, Toluene, Ethyl-benzene and Xylenes (BTEX), and <br /> Total Petroleum Hydrocarbons - Diesel (TPH-D). The soil samples were collected <br /> from the stockpiled soil (SP) and from the bottom of the excavation at a depth of <br /> approximately 7 feet below surface grade (bgs). BTEX constituents were not <br /> detected in the soil samples; however, TPH-D was detected at concentrations of <br /> 13 mg/kg (stockpile) and 130 mg/kg (excavation bottom). <br /> A "Notice of Responsibility" letter, dated January 8, 1998, was sent to Manteca <br /> Unified School District by PHS/EHD, requesting additional assessment of the <br /> diesel contamination. In response to the request a single temporary well (B 1/TW- <br /> 1) was advanced to 18 feet below ground surface (bgs), at the location of the <br /> former UST. Four soil samples were collected from below a depth of 7 feet. A <br /> groundwater sample was collected from the temporary well casing installed in the <br /> boring. <br /> Total Petroleum Hydrocarbons - Diesel (TPH-D) were detected in three of the <br /> four soil samples and the groundwater sample. TPH-D concentrations in soil <br /> ranged from 168 to 5.34 mg/kg, from soil samples collected at depths of 8 and 13 <br /> feet. TPH-D was not detected in the bottom hole sample at 18 feet below grade. <br /> No other contaminants were reported in the soil samples. MTBE was not detected <br /> by method 8260. Groundwater samples collected from B1/TW-1 had a reported <br /> concentration of 389 µg/1 TPH-D. <br /> Table of Laboratory Sam le Results (November 5, 1998) <br /> Sample LD. Gasoline I Diesel Benzene Toluene I E-Benzene Xylenes 8260 <br /> 18296-8 to 8.5' ND 168 m ND ND ND ND ND <br /> 18296-12.5 to 13 ND 43.1 m ND ND ND ND NA <br /> 18297-13 to 13.5 ND 5.34 m ND ND ND ND ND <br /> 18294-18 to 18.5 NA ND ND ND ND ND NA <br /> 18293-Groundwater NA 0.389 m ND ND ND ND ND <br /> ND=Non Detect <br /> 2.0 WORK PLAN <br /> M.J. Kloberdanz & Associates propose to drill 3 soil borings in the vicinity of the <br /> previously disclosed contamination to a depth at least ten feet below groundwater. All <br /> three of the borings will be completed as 2-inch groundwater monitoring wells. At least <br /> 2 <br />