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California gional Water Quality Co IB rd <br /> l \- Central Valley Region <br /> vKarl E. Longley,ScD, P.E., G ii\JJ ""°�: ` <br /> Linda S.Adams 9 Arnold <br /> Secre'ra� !or ?u DiRancho Cordova.California 956 av i% <br /> Emworm,enml Phone I( 1-1291 •FAX(916)464-4, Nc �tSehwarzeneg <br /> g <br /> er <br /> Prmecnat 11111, uucrhoards.ca.gov/centralvelley Governor <br /> ENP <br /> 511 CES <br /> 8 April 2009 <br /> Mr. Sergio Morescalchi <br /> Atlantic Richfield Company <br /> P.O. Box 1257 <br /> San Ramon, CA 94583 <br /> AMENDED BIOREMEDIATION PILOT STUDY WORK PLAN RESPONSE LETTER, ARCO/BP <br /> STOCKTON FUEL TERMINAL # 40T, 2700 WEST WASHINGTON STREET, PORT OF <br /> STOCKTON, SAN JOAQUIN COUNTY <br /> California Regional Water Quality Control Board, Central Valley Region (Regional Water Board) <br /> staff reviewed the 30 January 2009 Response Letter to the Regional Water Quality Control Board <br /> Letter dated December 3, 2008 (Response) submitted by Stantec Consulting Inc. (Stantec) on <br /> behalf of Atlantic Richfield Company, a BP Affiliated Company (ARCO). The Work Plan was <br /> prepared as part of an ongoing effort to implement an enhanced bioremediation pilot study. <br /> Our 3 December 2008 letter requested that ARCO (1) clarify the number of proposed injection <br /> points, (2) describe how the proposed baseline concentrations for calcium, sulfate, and sulfide <br /> were calculated and provide a baseline concentration for total dissolved solids (TDS), and <br /> (3) propose corrective action in the con inger4*yTlan to mitigate elevated concentrations of the <br /> injected chemicals and/or their byproducts at the compliance well (AR/MW-1) if those <br /> concentrations become significantly elevated above baseline levels. ARCO presented its <br /> preliminary response to Regional Water Board staff in a 7 January 2009 meeting and clarified <br /> that discussion in the Response. <br /> The Response includes a Work Plan for Amended Bioremediation Pilot Study (Work Plan) which <br /> proposes <br /> • To perform injections through seven injection points at five injection sites. These will include <br /> three existing injection wells (IS-1 through IS-3) at injection site AR/MW-5a and four injection <br /> sites to be created by installing one injection point each at AR/MW-3A, AR/MW-13A, <br /> AR/MW-8A, and AR/MW-13B. <br /> • To set baseline concentrations for dissolved calcium, sulfate, sulfide, and TDS at <br /> 71 milligrams per liter (mg/L), 27 mg/L, 0.2 mg/L, and 680 mg/L, respectively. The proposed <br /> baseline concentration for each analyte is the highest historical concentrations observed in <br /> AR/MW-1A. <br /> • To monitor AR/MW-1A for baseline exceedences of 120% or more for sulfate, TDS, and <br /> sulfide for a period of six months. If exceedences of TDS or sulfate are sustained, ARCO will <br /> implement a contingency plan of injecting a 100 mg/L fructose solution to reduce sulfate to <br /> sulfide. If exceedences of sulfide are sustained, ARCO will inject air to oxidize sulfide to <br /> sulfate. <br /> • Not to implement a contingency plan for calcium. <br /> California Environmental Protection . tgency <br /> Q� RecTcled Pope, <br />