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EDMUND G. BROWN JR. <br />GOVERNOR <br />C•LIFORNI• <br />Water Boards 301?„ <br />M ATTHEW RODRIQUEZ <br />SECRETARY FOR <br />ENVIRONMENTAL PROTECTION <br /> <br />Central Valley Regional Water Quality Control Board <br />11 October 2017 <br />Karl Bewly <br />Chevron EMC <br />145 S. State College Boulevard, Room 5032 <br />Brea, CA 92821 <br />FORMER CHEVRON STATION #9-8632, 575 W. GRANT LINE ROAD, TRACY, SAN <br />JOAQUIN COUNTY, CASE# 390842 <br />Central Valley Regional Water Quality Control Board (Central Valley Water Board) staff <br />reviewed the Work Plan Second Addendum (2nd Addendum) submitted on your behalf by GHD <br />Inc. (GHD) for the Chevron Station #9-8632 located at 575 W. Grant Line Rd in Tracy (Site). <br />In the 2nd Addendum, GHD proposes advancing 5 borings to collect shallow soil for comparison <br />to Direct Contact and Outdoor Air Exposure requirements established by the State Water <br />Resources Control Board's Low Threat Underground Storage Tank Case Closure Policy (LTCP) <br />as well as to address waste oil tank soil sampling requirements. GHD also proposes collecting <br />another round of soil gas sampling from wells VP-1 through VP-4. The borings are proposed as <br />follows: <br />Location Total Depth <br />(ft bgs) <br />Soil Sampling Depth(s) <br />(ft bgs) <br />Analysis <br />B-1 thru B-3 6 4.5, 6 TPHg, benzene, ethylbenzene, naphthalene <br />B-4 6 4.5,6 TPHg, TPHd, TPHd-SGC, TOG, VOCs, SVOCs, <br />PCBs, PAHs, Title 22 metals <br />B-5 Not Specified Not Specified Title 22 metals <br />TPHg=total petroleum hydrocarbons as gasoline; TPHd=TPH as diesel; TPHg-SGC=TPHd with Silica Gel Cleanup; TOG=total oil <br />and grease; VOCs=volatile organic compounds; SVOC=semi-VOCs, PCBs=polychlorinated biphenyls; PAHs=polycyclic aromatic <br />hydrocarbons; ft bgs=feet below ground surface <br />Central Valley Water Board staff has the following comments: <br />In the 2nd Addendum, GHD does not specify the sample depth for the B-5 soil samples, <br />stating that only one soil sample will be collected from boring B-5 at "? fbg". In a phone <br />call on 11 October 2017 between Mr. Morgan Hargrave of GHD and the Central Valley <br />Water Board staff, Mr. Hargrave indicated that GHD proposes to collect a soil sample in <br />B-5 at 5 feet below ground surface. <br />With the inclusion of Comment 1 above, the proposed borings are sufficient to address <br />the waste oil tank soil sampling and LTCP Direct Contact and Outdoor Air Exposure data <br />KARL E. LONGLEY ScD, P.E., CHAIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFFICER <br />11020 Sun Center Drive #200, Rancho Cordova, CA 95670 I www.waterboards.ca.govicentralvalley <br />0 RECYCLED PAPER