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Cp-"2- ool <br /> ENVIRONMENTAL HEALTH DEPARTMENT <br /> SAN JOAQUIN COUNTY <br /> Unit Supervisors <br /> na DonK. Heran, R.E.H.S. <br /> �✓ 304 East Weber Avenue, Third Floor Cart sorgman, R.E.H.S.Director Mike Huggins, R.E.H.S.,R.D.I. <br /> == -`'x ,1•. io n� -2708Al Olsen, R.E.H.S. SCOClCOl1, Calfa95202 <br /> Douglas W. Wilson,R.E.H.S. <br /> \�•. ---- ,o- <br /> Program Manager TtlepkloRe: (?09) 46$-33420 Margaret l.agorio, R.E.H.S. <br /> \_F6R Laurie A. Cotulla,R.E.H.S, <br /> Fax: (20 ) `I-D1 $ Robert NfcClellon,R.E.H.S, <br /> PrUgrcymlffar:ager <br /> 'r <br /> Mark Barcelios,R.E.H.S. <br /> JERRY MOORE DEC 20.03 <br /> MOORE PETROLEUM <br /> PO Box 67 <br /> BANTA CA 95304 <br /> Site Coue: 15 02 <br /> RE: Work Pian for Ozone Spar in g g <br /> 5491 F Street <br /> Banta CA 95304 <br /> San Joaquin County Environmental Health Department (EHD) has received and <br /> reviewed Work Plan for Ozone Sparging (WP), dated 26 September 2003, <br /> prepared. by Apex Envirotech, Inc. (AEI). The site has been under sail vapor <br /> extraction (SVE) remediation off and on :since .1.995. To date, approximately <br /> 4,369 pounds. of hydrocarbons have been removed from the vadose zone with. <br /> the current remediation system. Contaminantconcentrations in ground water.has. <br /> not responded as well as was expected, therefore AE] proposes to enhance the <br /> SVE system by adding an ozone sparging system to breakdown dissolved <br /> hydrocarbons and other fuel components. <br /> To better evaluate this WP, EHD reviewed various quarterly reports, boring logs, <br /> and previous directives to characterize the site status. The subsurface of the site <br /> appears to consist predominantly of silt and minor clay at 5 feet bsg: primarily of <br /> sand at 10. 15 and 20 feet bsg: and more commonly silt and/or clay, and less <br /> commonly sand at 25 feet bsg. Limited data suggest that sand occurs between <br /> 30 and 40 feet bsg. The thick sand sequences are suggestive of deposition in or <br /> near a former stream channel. The fine grained soil at 25 feet below surface <br /> grade (bsg) does not appear to be an effective barrier to vertical migration of <br /> dissolved contaminants as sand occurs locally at that depth. <br /> The vertical extent of impacted soil appears to be reasonably delineated. Data <br /> reviewed by EHD is too limited to determine if the lateral extent of impacted soil <br /> has been delineated, but most of the impacted sail appears to occur at 10 feet <br /> bsg in the data reviewed, suggesting smear zone contamination on the capillary <br /> fringe. <br /> Ground water occurs at approximately 11 feet bsg and the depth to water has <br /> .✓ varied by only a few feet since monitoring began on the site (circa 1988). Ground <br /> water flows predominantly toward the northeast, on occasion varying toward the <br />