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y 'ARCO #2133 � � `� Page 2 of 2 Petroleum Constituents in Soil s 5 Feet bgs C'>5 Feet bgs and 510 Feet bgs C Unknown Soil Concentrations of Benzene C>1.9 mg/kg and s 2.8 mg/kg G>2.8 mg/kg and<8.2 mg/kg Ci>8.2 mg/kg and 512 mg/kg C>12 mg/kg ands 14 mg/kg G>14 mg/kg ,G Unknown Soil Concentrations of EthylBenzene C>21 mg/kg and s 32 mg/kg C>32 mg/kg and 5 89 mg/kg C'>89 mgtkg and s 134 mg/kg C>134 mg/kg and<-314 mg/kg C->314 mg/kg G Unknown Soil Concentrations of Naphthalene C>9.7 mg/kg and 5 45 mg/kg C'>45 mg/kg and 5 219 mg/kg G>219 mg/kg G!,Unknown Soil Concentrations of PAH: - - G>0.063 mg/kg and 5 0,68 mg/kg O>0.68 mg/kg and 5 4.5 mg/kg G>4.5 mg/kg IF Unknown Area of Impacted Soil G Area of Impacted Soil>82 by 82 Feet G Unknown ` Additional Information Should this case be closed in spite of NOT meeting policy criteria? Explain: DTW on site approx. 8 feet bsg, but impact to groundwater minimal, maximum benzene concentration 450.ppb, detected only in one well; MTBE as high as 67 ppb in four wells; plume length indeterminable as this is a commingled site but is probably on the order of 150-200 feet; nearest water supply well approx. 800 feet away, so LTCP criteria slightly missed. Soil at approx 5 feet bsg passes Table 1 criteria, but soil at.10.5 to 11.5 feet bsg locally does not for ethylbenzene, which may well be r') YES r-' NO applicable to 10 feet bsg in the same areas; however, the consultant notes the site iscommercial and paved with an incomplete exposure pathway to residential or commercial occupants with only construction workers potentially exposed to impacted soil. The site is in the closure process; destruction of the site corrective action wells is pending. SPELL CHECK Save in Pro9 rens. Save as Final LOGGED IN AS HENDERSONN CONTACT GEOTRACKER HELP i https:Hgeotracker.waterboards.ca.gov/regulators/screens/closure_policy.asp?global_id=T06... 8/1/2013