Laserfiche WebLink
� F <br /> • • FILE COPY <br /> installation of at least four continuous core boreholes given the strength of the plume documented near <br /> MW-11. Two boreholes should be placed on-site near SB-3/VW-4,and two off-site near MW-11 to at least <br /> 80 feet below grade surface(bgs) collecting both soil and groundwater samples from significantly different <br /> lithologic units focusing on preferential flow paths (high hydraulic conductivity units in the saturated zone). <br /> The minimum depth shall be at least 80 feet recognizing that sites within 100 feet of this facility have <br /> documented high levels of hydrocarbon contamination in groundwater found in high hydraulic conductivity <br /> flow paths at greater than 80' bgs. In addition historic depth to water during the operational period of this <br /> facility have been recorded at equivalent depths. Following the continuous core work, monitor wells shall <br /> be installed purposefully constructed to evaluate mass flux in preferential flow paths. <br /> The workplan and past quarterly monitoring reports have failed to report any analyses for 1,2-DCA, EDB, <br /> MtBE, LAME, EtBE, DIPE, tBA, McOH and EtOH consistently. The responsible party at this site must <br /> sample and analyze all soil and groundwater for these compounds in addition to TPHg, TPHd, and BTEX <br /> during subsurface assessment and groundwater monitoring events until further written notice. <br /> The workplan has been conditionally approved and must be implemented within 30 calendar days <br /> from the date of this letter. Assessment of the vapor extraction remediation system effectiveness and <br /> potential enhancement shall be completed and reported to PHS/EHD within 60 days of the date of <br /> this letter. Please submit an addendum to the workplan and a single revision to the most recent <br /> QMER with those items requested above to PHS/EHD no later than May 15,2000. <br /> Failure to comply with the directives above may result in referral to the San Joaquin County District <br /> Attorneys Office. <br /> Please submit technical reports to the San Joaquin County Public Health Services Environmental Health <br /> Division(PHS/EHD),Attention: Ron Rowe. <br /> PHS/EHD recommends that all site assessment and remediation related activities in which the <br /> responsible party(s) engages in and anticipates reimbursement from the Underground Storage Tank <br /> Cleanup Fund(USTCF)be reviewed and cost pre-approved prior to commencing work. <br /> Should you have questions regarding this correspondence please contact Ron Rowe at(209)468-0342. <br /> Donna Heran,REHS,Director <br /> Environmental Health Division <br /> Ronal` d Rowe Sr.REHS Margaret agorio,Supervisor <br /> Site Mitigation Unit Site Mitigation Unit <br /> CC: <br /> CVRWQCB—Marty Hartzell <br /> SIC District Attorney—David Irey <br /> 440CHARTERWPITR2 <br /> 2 , <br />