Laserfiche WebLink
ENVIRONMENTAL INVESTIGATION REPORT <br /> Unocal Service Station No 5886 <br /> 2701 west March Lane <br /> Stockton,Cahforma <br /> Delta Project No D091-066 <br /> ' Page 20 <br /> No detectable hydrocarbons were detected in soil samples collected beneath the former <br /> USTs <br /> No detectable q <br /> hydrocarbons quantified as TPH as gasoline were detected in soil samples <br /> Y <br /> ' collected beneath or In the vicinity of the former USTs TPH quantified as diesel was <br /> detected in soil in the vicinity of the former tanks at a maximum concentration of 4 5 mg/kg <br /> Detectable hydrocarbons quantified as both TPH as gasoline and diesel were detected in soil <br /> ' samples collected In the vicinity of the former northern and southern dispenser islands <br /> Detectable concentrations of TPH as gasoline ranged from 2 5 mg/kg to 29 mg/kg, and <br /> ' detectable concentrations of TPH as diesel ranged from 1 1 mg/kg to 1,100 mg/kg <br /> Approximately 0 17 gallons quantified as diesel was released during the installation of <br /> shoring around the UST's prior to their removal The volume of possible previous releases <br /> is unknown <br /> Benzene was detected in one Geoprobe (GP-17) water sample at a concentration of 3 2 µglL <br /> iand In the ground water samples collected from the tank cavity Ground water impacted by <br /> benzene appears to be restricted to the tank cavity area and southwest of the tank cavity <br /> A concentration of 7 3 pig/L of benzene was initially reported in the ground water sample <br /> ' from the tank excavation However, following the removal of impacted fill material and <br /> 15,000 gallons of ground water, benzene was detected at concentrations below the action <br /> ' level 1 0 p.g/L for drinking water <br /> The installation of three on-site ground water monitoring wells is proposed to assess the <br /> ground water flow direction, the ground water gradient, and the dissolved hydrocarbon <br /> concentrations <br /> RPT16o S75 <br /> I� <br />