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1665.Pacific Avenue, Stockton <br /> Page 2 <br /> pump island area. The pump island area was discussed in the CSM (area of KB-3 and KB-5) as <br /> an area of residual soil contamination. It was also discussed in the CSM that the groundwater <br /> rising into the zone of contaminated soil creates a significant smear zone. EHD agrees with this <br /> conclusion. <br /> Tables 4-1 and 4-2 in the CSM list potential soil and groundwater cleanup criteria. The water in <br /> San Joaquin County is of potential beneficial use and the cleanup levels are the numerical <br /> objectives designated in the water quality control plan. Sites may receive "No Further Action <br /> Required" letters prior to meeting the basin plan numerical objectives but data must be used to <br /> show when the water will meet the objectives. The mass of contaminants remaining in the soil <br /> must be calculated and shown to not be a continuing source of contamination to groundwater. <br /> In addition, to justify leaving contaminated soil in place the potential health hazards of <br /> direct exposure, vapor emissions to indoor air, and gross contamination (odor, <br /> nuisance, gross pollution) from the soil must be evaluated. Currently, the CVRWQCB <br /> and EHD use the San Francisco Bay Regional Water Quality Control Board <br /> ,,(SFBRWQCB) Environmental.Screening Levels electronic version lookup tables (ESL <br /> Surfer-October 2005) to evaluate if the contaminated soil can remain in place. Sites <br /> that have contaminant concentrations in soil that exceed the SFBCVRWQCB ESL <br /> Surfer concentrations must provide additional justification such as soil vapor sampling <br /> data or use of a model like the Johnson & Ettinger Model. <br /> The CSM states that the ozone sparge system should be re-evaluated since it no longer <br /> seems to be effective in reducing the contaminants. '.EHD agrees that the ozone system <br /> should be re-evaluated. Since groundwater contamination on-site doesn't appear to be <br /> in the 85 to 90 feet zone, disconnection of the "C" zone sparge wells may be <br /> appropriate. <br /> If you have any questions contact me at (209) 468-3449. <br /> Donna Heran, REHS, Director <br /> ,Environmental Health Department <br /> Margaret Lagorio, REHS <br /> Program Coordinator Unit IV <br /> c: Jim Barton — CVRWQCB <br /> David trey— SJCADA <br /> Ms. Helen McCrary <br /> William Glenn-- ENSR <br />