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California Regional Water Quality Control Board ; Central Valley Region e.. ..-'Y Robert Schneider,Chair Terry Tamminen Sacramento Main Office Arnold Schwarzenegger Secretary for Internet Address: http://w .swrcb.ca.gov/mgcb5 Governor Environmental 11020 Sun Center 16)464-3 Rancho(1)Cordova,CA 95670-6114 �,, EU Protection Phone 916 464-3291 Fax 916 464-0797 ((`JVD \\V/) U FEB 0 9 2004 6 February 2004 ENVIRONMENT HEALTH PERMIT/SERVICES Mr. Arnold Hof 28537 E. River Road Escalon, CA 95320 DELINQUENT REPORTS, FORMER CAL FARM SUPPLY, 2040 WEST WASHINGTON STREET,STOCKTON, SAN JOAQUIN COUNTY In a 30 April 2003 letter, staff of the Regional Water Quality Control Board(Regional Board staff) provided you with a draft Monitoring and Reporting Program, and requested that you destroy monitoring wells MW-8 and MW-9, install a replacement well for MW-6, and document the phytoremediation activities you planned to take pursuant to our October 2001 meeting. We have not received any communication from you on any of the above items in spite of telephone conversations you had with Ms. Amy Terrell of my staff on 1 July and 14 July 2003, during which you stated that you were intending to discuss these matters with your consultant, Mr. David Smith of HydroGeologic Inc. Ms. Terrell again spoke to you about these items on 17 September. Replacement for MW-6 Not Required As Ms. Terrell discussed with you during the 17 September telephone conversation,Regional Board staff do not believe that the nitrogen concentrations found in MW-6 before it was inadvertently destroyed were related to past practices at Cal Farm Supply. MW-6 was on the south side of the southern half of the former Cal Farm Supply property about 200 feet south of the fertilizer handling operations. Between 1997 and 1999, the period of record for MW-6, nitrate (as nitrogen) concentrations ranged between 216 and 367 mg/l,whereas concentrations of nitrate (as nitrogen) in monitoring wells on the northern half of Cal Farm Supply's property ranged from 0.5 to 76 mg/1 during this same period. South of MW-6, Koppel Stockton Terminal (Koppel) is remediating groundwater polluted with nitrate. At the Koppel site,monitoring well KP-2 is about 300 feet south of former MW-6, and nitrate (as nitrogen) concentrations in KP-2 ranged from 150 to 240 mg/l during the period of record for MW-6. The groundwater gradient is not consistent between these two sites. Based on elevations obtained from Cal Farm Supply's monitoring wells, the gradient vaned from southerly to northeasterly at MW-6, and from Koppel's monitoring well data the gradient is consistently southerly at KP-2. Based on the large difference in nitrogen concentrations between Cal Farm Supply and Koppel, and the location of MW-6 south of Cal Farm Supply operations, Regional Board staff do not believe that you are responsible for the nitrate detected in MW-6. Therefore, you are no longer required to replace this well. California Environmental Protection Agency Q-1 Recycled Paper