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California Regional Water Quality Control Board (\� Central Valley Region vRobert Schneider Chair Terry Tamminen D /� Sacramento Main Office /,y /� old Schwarzenegger Secretary for S l� �r� Internet Address: http://�.s�b.ca.gov/mqcb5 b.ca.gov/mgcb5 nor Environmental 11020 Sun Center Drive#200 Rancho Cordova,CA 95670-6114 Protection Phone(916)464-3291 Fax(916)464-4797 23 Au E pVl AUGAp MEN 20pq August 2004 ERMITjSERV CES TN Mr. Paul Supple Atlantic Richfield Company P.O. Box 6549 Moraga, CA 94570 REVIEW OF PROPOSED NEW BASELINE LEVELS, ARCO/BP FUEL TERMINAL, 2700 WEST WASHINGTON STREET, PORT OF STOCKTON, SAN JOAQUIN COUNTY Staff of the Central Valley Regional Water Quality Control Board(Regional Board) reviewed the 23 July 2004 Pilot Study Implementation Report(Implementation Report) and the 9 August 2004 Proposed New Baseline Levels (Revised Baseline Report) submitted by URS Corporation on behalf of Atlantic Richfield Company(ARCO) for the ARCO/BP Stockton Fuel Terminal#40T in Stockton. The Implementation Report discusses the enhanced bioremediation pilot study injection system installation, operation, and monitoring as required by Waste Discharge Requirements (WDRs) Order No. R5-2003-0164. The following are the comments originally provided on 28 July 2004 by email: 1. ARCO needs to include a discussion of the laboratory results. The laboratory flagged a considerable amount of data for various reasons including holding time and continuing calibration verification check exceedences. ARCO must discuss this information and how it affects the validity of the data. 2. ARCO needs to discuss the field monitored parameters. Conductivity results appear to be increasing and ORP results appear to be sporadic with no trend. ARCO needs to discuss significant field monitoring data and explain what the data indicate about the enhanced bioremediation pilot study. The Revised Baseline Report proposes revised baseline concentrations for the enhanced bioremediation pilot study. On 21 May 2004, Regional Board staff concurred with the baseline levels proposed in the 11 May 2004 REVISED Baseline Summary Report Enhanced Bioremediation Pilot Study. After four weekly sampling events, it was noted that concentrations of several constituents were greater than 20 percent above the baseline concentrations in monitoring well AR/MW-lA. As required by WDRs Order No. R5-2003-0164, ARCO stopped the weekly injections of sulfate/nitrate and collected confirmation samples. Based on the results of the confirmation samples, there appears to be a seasonal fluctuation in concentrations not observed during the baseline sampling events. Constituents that exceed baseline concentrations in AR/MW-lA did not exceed baseline in the seven monitoring wells in between the injection wells and AR/MW-lA. Therefore, ARCO proposed revising the baseline concentrations for AR/MW-IA. California Environmental Protection Agency �a Recycled Paper