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CHEVRON EMC "?58420213 09/19 '00 "'•:58 NO.075 02/10 <br /> l <br /> California regional Water Quality Control Board. <br /> Central Valley Region. <br /> Winston H.Hickox Steven T.,Butler,Chair <br /> Secretary for Gray oavis <br /> Envlronmental Sacramento Main Office Goy ernor <br /> Prole"Ilan intcrnet Address; httn;//wwwswrcb.ca.gov/-�rwgcb5 <br /> 3443 Rootier Road,Suirc A,Sacrxmcnto,California 95827-3003 <br /> Phonc(916)255-3000-FAX(916)255-3015 <br /> 3 August 2000 RECEIVED <br /> "Q^'�u�rrAu - <br /> i01 tf ti IMAW <br /> 7 2000 <br /> Mr. Robert D. Mibalovich. <br /> Pipeline Program.Manager '0,A01INALOVICH <br /> Chevron.Fnvironm.ental.Management Company <br /> P. 0. Box 601.2 <br /> San Ramon., CA 94583-071.2 <br /> APPROVAL OF WORK PIANS FOR CT-IICVRON WPIIJ LTNIC SITES <br /> I have reviewed the 30 June 2000 work plans for Chevron.'s pipeline sites at Bruns/Carlson.property, <br /> Lyoth Loading Station., Mansfield property, anal.Thompson Chevrolet.My comments on.these wort <br /> plans are presented below, <br /> Bruns/Carlson Property, Byron, Contra Costa County <br /> The work plan proposes to sample monitoring wel.l.s (MWs) 1-4 to determine levels of total petroleum. <br /> hydrocarbons as diesel(TPHd) levels withand without silica gel Cleanup. The work plan.also proposes <br /> to resample GB-6B for. TPHd testing with.and without silica gel cl,ean.up. My 14 March 2000 letter. <br /> requested TPHd only without silica gel cleanup. However, Chevron plara.s to collect samples for TPHd <br /> testing with silica.gel cleanup to compare results from the two tests. Th.e work plan adequately addresses <br /> my concerns and is hereby approved. <br /> former Iyolh Loading Station, Tracy, San Joaquin County <br /> My 14 Manch letter requested, definition.of the lateral extent of the TPI-id plumes at MWs 6 and 7 via. <br /> installation,of a MW downgi;adient of MWs 6 and 7. The work plan.proposes to insto.l.l a <br /> boring/temporary well.downgradient of 7, collect groundwater samples, and <br /> sample collection,. The work plan is inadequate because it does n,ot propose a permaocnt MW <br /> boringut the after. <br /> downgradi.ent of MW7. Jn addition, it does not h:"ve provisions to define the lateral extent of the TPJ-Id <br /> plume at MW 6. The work plan is conditionally approved provided.that Chevron,installs a MW <br /> downgradient of MW-7 and defines the plume at MW-6. <br /> ,Mansfield Property, Tracy, Sall Joaquin County <br /> My 14 March letter requested resamplin.9 of: locations B5, B6, B7,139, and B12 for TPHd analysis <br /> without silica gel cleanup. The work plan proposes resampling J35, 137, and B9 only, but does not: <br /> provide the rationale for. eiimi.nation of B6 an.d.B1.2. These locations need to be in.clud,ed. in i:he sampJi.ng <br /> program.to provide suffi,ci.Ent coverage of the area downgradient of TPH-affected soil. The work plan.is <br /> conditionally approved provi.d.ed that B6 and B12 are i.nclu.ded in the sampling program.. <br /> •r <br /> California Fnviro,nttceniplprotection Agency <br /> `GC�Recycled paper <br />