Laserfiche WebLink
If contamination is remaining, describe concentration range and volume (cubic yards or meters) <br /> Some soil contamingion is rgmaminiz near monitoring wells MW3. MWS and MW6 TPH as diesel <br /> r ND-28 m /k TPH as gasoline ND-130 nij!/kiz, Volume unknown <br /> Table III - Maximum documented contaminant concentrations in soil before and after cleanup <br /> Method Before After Depth Method Before After Depth <br /> Contaminant used (mg/kg) (mg/kg) 00 Contaminant used (mg/kg) (mg/kg) 00 <br /> Excavation Excavation ND ND 1075 <br /> TPH(Gas) 22 ND 1075 Benzene <br /> Excavation Toluene Excavation ND ND 1075 <br /> TPH (Dieset) 120 95 105 <br /> Other fuel Ethylbenzene Excavation ND ND 1075 <br /> (TOG) <br /> Heavy metals Xylene Excavation 0 010 ND 1075 <br /> (Zinc) <br /> Other Other <br /> IV. Groundwater Remediation Information <br /> Groundwater remediation method(s) None <br /> Volume treated and/or removed None <br /> If contamination is remaining, describe concentration range and volume (gallons or liters) Diesel ND- <br /> 4 0 m IL Gasoline ND-14 0 m /L Benzene ND-5 3 m IL This contamination is likely the result <br /> of operations from adjacent sites Volume unknown <br /> Table IV - Maximum documented contaminant concentrations in groundwater <br /> before and after cleanup <br /> . LVHeavymeLals <br /> Method Before After Depth Method Before After Depth <br /> nt used (mg/L) (mg/L) (ft) Contaminant used (mg/L) (mgiL) (ft) <br /> 40 - Benzene 5 3 <br /> sel) - 14 0 Toluene 042 <br /> Ethylbenzene 1 9 <br /> talsXylene 2 6 <br /> 0 02 Other— <br /> hene <br /> V Closure <br /> Does Regional Board concur with closures Yes ✓ No� <br /> Rationale for closure 1 Based on current data the soil and groundwater contamination due to <br /> under Yround storage tank UST o erations at the Unocal site have been remediated 2 The residual <br /> petrol-,um contammation occasionally detected in Unocal well MW3 is likely the result of operations at <br /> e adjacent site Well MW3 is side gradient from the former UST locations at Unocal and down <br /> gradient from the operations at 1he adjacent site 3 The chlorinated and petroleum h drocarbon <br /> contamination in Unocal well MW5 is likely caused by other adjacent terminal operations This well is <br /> closer to piezometers and monitoring wells installed on adjacent sites and quite distant from the former <br /> Unocal UST locations, In addition 1 2-dichloroethane was only detected in Unocal well MW5 and not <br /> in other Unocal wells <br /> Location of reports on file (Agency/Room) <br /> County Staff person Phone <br /> Regional Board office Sacramento Staff person P S Isorena Phone 916 255-3049 <br />