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CAMBRIA REGULATORY STATUS REVIEW AND RECOMENDATIONS i The site appears to meet the CVRWQCB criteria for a low-risk groundwater designation As outlined in Appendix B of the"Tri-Regional Board Staff Recommendations for Preliminary Investigation and Evaluation of Underground Tank Sites" a low-risk groundwater case has the following general characteristics 1 Contaminants remaining in the vadose zone must not reverse or threaten to reverse the mass reduction rate of groundwater pollutants, 2 Separate phase product has been removed to the extent practicable, 3 No existmg water-supply wells, deeper aquifers, surface waters,or other receptors are threatened by pollutants remaining in the aquifer, and 4 The total pollutant mass remaining in the groundwater is decreasing at predicted rates and neither creates,nor threatens to create, a risk to human health and safety or future beneficial use(s)of the • aquifer Contaminants remaining in the vadose zone must not reverse or threaten to reverse the mass reduction rate of groundwater pollutants: Soil analytical results from investigations including,and subsequent to,the tank removal activities during January 1999 demonstrate that the residual petroleum hydrocarbons and MTBE in soil are limited to the northwestern dispenser area Soil delineation is discussed above Cambria conducted a 5-day SVE test at the site during November 2001 After the SVE test,a confirmation boring(VE-3)was placed in the source area,adjacent to the boring with the highest MTBE detections (SB-2) No MTBE was detected in the confirmation boring The soil analytical data collected from this confirmation boring indicate that the SVE test was successful in removing a significant amount of the residual source material from the soil beneath the northwestern dispenser and suggest there is little or no remaining source material in the vadose zone Therefore, it is unlikely that any remaining mass in the vadose zone would impact groundwater beneath the site Separate phase product has been removed to the extent practicable Separate-phase hydrocarbons have never been observed at this site No existing water-supply wells,deeper aquifers,surface waters, or other receptors are threatened by pollutants remaining in the aquifer The nearest sensitive receptor is a municipal supply located . immediately southwest of the subject site However, groundwater analytical results from the site 1346 5