Laserfiche WebLink
r ' <br /> ENVIRONMENTAL HEALTH DEPARTMENT <br /> SAN JOAQUIN COUNTY <br /> > Unitsupe"isors <br /> Donna K. Heran, R.E.H.S. Carl Bergman, R E .H.S. <br /> Director 304 East Weber Avenue, Third Floor g <br /> �tll�.� li Mike Huggins R E H S. , R.D. I. <br /> R� . . AI Olsen, R.E.H.S. Stockton , California 95202-2708 15onglasW. Wilson. R.E.H.S . <br /> sb � s <br /> cg4r-oac'e Prograin Manager Telephone: (209) 468 -3420 Margaret L.agor,o, R .E.ILS. <br /> _ Laurie A. Cotulla, RXILS. Fax: (209) 464-0138 - Robert McClcllon, R.E.tr.S. <br /> Progrmn Manager Mark Barcellos, R.E.H.S. <br /> RODGER LISTON MAR 0 7 2Gu5 <br /> DARPETRO INC USA SERVICE STATION <br /> 3450 EL CAMINO <br /> CERES CA 95307 <br /> RE: DARPETRO, INC Site Code : 1060 <br /> 749 E CHARTER WAY <br /> STOCKTON, CA 95202 <br /> San Joaquin County Environmental Health Department (EHD) has received and <br /> reviewed Work Plan (WP), dated 16 October 2004, to install three groundwater <br /> monitoring wells and one assessment boring. EHD has also received a letter dated 15 <br /> October 2004 confirming a decision between EHD and your consultant California <br /> Geophysical Group, Inc, (CGG), to omit the soil gas survey of the site at this time. <br /> CGG proposes in WP to advance one boring to a target depth of 50 feet below surface <br /> grade in the former UST pit to collect soil samples at 5-foot intervals and grab ground <br /> water samples at 10-foot intervals until two consecutive ground water samples test 'non- <br /> detect' for gasoline components, the chemical analyses to be performed by an on-site <br /> mobile laboratory. In addition , CGG proposes to install three ground water monitoring <br /> wells, MW-14, MW-15 and MW-16 near the southwest corner of Charter Way and Grant <br /> Street and east-southeast and north-northeast of the former UST pit to assess the lateral <br /> extent of impacted shallow groundwater. EHD approves_ installation of the the <br /> ro osed roundwater monitoring wells, but with therovlsion a he sand felt r pack <br /> exefi-d only 2 eef'a o>♦ve eac lscreen interval . the grout seal sal be r�oerly mi&ed <br /> po an cemen wit a maximum of 5% bentonite, ppprove for grouting by the,_, <br /> manufacturer; mixed M the cement. <br /> EHD cannot approve advancement of the assessment boring at this time as the methods <br /> - - <br /> for advancing the boring and collecting soil and groundwater samples ll'ave notn <br /> specified. Also, EHD is still concerned that the approach for defermining" tfie dotal depEh <br /> of the proposed boring in the former UST pit area utilizing a mobile lab may not be a <br /> cost-efficient method . EHD recommends that you do a cost estimate comparison for <br /> utilizing a mobile laboratory with the attendant drill rig standby time while analyzing <br /> samples vs. advancing a boring to a specified target depth likely to achieve vertical <br /> delineation, collecting groundwater samples and submitting them to a non-mobile <br /> laboratory facility. EHD notes that the State Water Board Cleanup Fund (Fund) may <br /> decline reimbursement of costs if the Fund decides the expenses submitted are <br /> excessive. EHD also recommends consideration of use of a cone penetration testing <br /> . - -_._.. <br /> (CPQ) rig. to advance the boring an o 'collect groundwater samples from each lnferrval <br /> of potential high permeability and..submitting the samples to a non-mobile analytical <br /> laboratory facility. Please provide a work plan addendum to EHD by 18 April 2005 that <br />