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California Regional Water Quality Control Board ;: ` : <br /> Central Valley Region �ti �.l <br /> Winston H.Hickox Sacramento Main Office Gray Davis <br /> Secretaryfor Internet Address: http://www.swrcb.ca.gov/—rwgcb5 Governor <br /> Environmental 3443 Routier Road,Suite A,Sacramento,California 95827-3003 <br /> Proteclion Phone(916)255-3000•FAX(916)255-3015 <br /> 29 December 2000 <br /> G'1 •tat � . <br /> Al Jesena <br /> Naval Facilities Engineering Command, West <br /> 900 Comodore Drive, Bldg. 205/1 <br /> San Bruno, CA 94066-5006 <br /> BUILDING 508 AND 617 0 W REMEDIAL INVESTIGA TION DRAFT WORKPLAN <br /> (Work Plan), NA VAL COMPUTER AND TELECOMMUNICATIONS STATION, SAN <br /> DIEGO DETACHMENT, STOCKTON <br /> Thank you submitting the subject document for additional investigations for the oil water <br /> separator(OWS) sites at Buildings 508 and 617. The document was dated 15 December 2000, as <br /> prepared by CH2MH111. Please address the following comments in a Final Work Plan: <br /> 1. 4.0 Field Work Objectives and Scope, Phase 2-Well Installation <br /> The Work Plan states that, "The wells will generally be,placed with one well up-gradient <br /> (or in the source)...." The Navy should ensure that a background monitoring well is <br /> installed at both sites in order to develop background levels for metals in groundwater. <br /> 2. Phase 3-Quarterly Sampling <br /> The Work Plan states that, "...two rounds of quarterly sampling will be accomplished." <br /> The Field Schedule in section 8 shows "quarterly" sampling to occur on.02/19-02/23 and <br /> 02/26-03/01. This appears to be two sampling events rather than quarterly sampling based <br /> -on an annual schedule. Please delete the term "quarterly" from this section and the Field <br /> Schedule. Revise the text to reflect the fact that two sampling events will occur to gather <br /> information in support of monitoring well locations. <br /> Secondly, metals and SVOCs are not included in the list of constituents to be analyzed <br /> during the groundwater well sampling event. As shown on Figure 2, Building 508 has <br /> shown high levels of arsenic and barium. Please include all constituents of concern <br /> (COCs) to ensure that the extent of all contaminants is delineated. <br /> 3. Figure 4 shows the proposed sampling locations for GeoprobeTM groundwater sampling. <br /> Constituents found in B508-6 include 18,000 ppb diesel, 17,000 ppb motor oil, 29,000 ppb <br /> gasoline, and high levels of BTEX. The Navy should include an additional sampling <br /> location downgradient to the west of B508-6 to delineate the extent of the plume in that <br /> direction. Furthermore, the Navy should consider step-out/down criteria when delineating <br /> the extent of the plume in all levels of the unconfined aquifer at both locations. <br /> California Environmental Protection Agency <br /> c� Recycled Paper <br />