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lawuNuxG BRowx JR <br /> A11. <br /> .......... Mrl,ur,u,ROnxxuu[ r,vx <br /> Water Boards <br /> Central Valley Regional Water Quality Control Board <br /> °'l- oKY - o 3 O I T <br /> 21 December 2012 (Q <br /> Mr. Roger Smith — fOuAt <br /> Glenn Springs Holdings, Inc. <br /> 5005 LBJ Freeway, Ste 1350 <br /> Dallas, TX 75244-6119 <br /> MONITORING WELL DESTRUCTIONS AND SOIL SAMPLING SCHEDULE, OXYCHEM <br /> STOCKTON, 1904 CHARTER WAY, SAN JOAQUIN COUNTY <br /> Staff of the California Regional Water Quality Control Board, Central Valley Region (Central <br /> Valley Water Board) reviewed a 20 November 2012 email request from your consultant, Mr. <br /> Matt Sutton of The Source Group. Mr. Sutton requested that the annual soil sampling obligation <br /> be removed from the phytoremediation treatment procedures, and questioned why monitoring <br /> wells MW-3 and MW-4 were included in the monitoring schedule. This letter addresses these <br /> two inquiries. <br /> Monitoring Well Destructions <br /> A staff review of the file correspondence shows that MW-3 and MW-4 were installed for the <br /> purpose of evaluating the underground fuel tanks and were no longer a necessary component <br /> of the monitoring program. In a 5 August 2002 letter, Central Valley Water Board staff <br /> concurred with OxyChem's proposal to destroy them. In my 27 November 2012 telephone <br /> conversation with Mr. Sutton, he confirmed that the wells had not been destroyed. <br /> Staff review of the monitoring reports finds that intermediate monitoring wells MW-19, MW-22, <br /> and MW-24 have consistently been beyond the footprint of the shallow zone groundwater <br /> pollution, and are unlikely to provide useful data. Therefore, by 1 March 2013, please provide a <br /> workplan to destroy MW-3 and MW-4, and if desired, monitoring wells MW-19, MW-22, and <br /> MW-24. The wells shall be destroyed according to San Joaquin County regulations. <br /> Soil Sampling Schedule <br /> The phytoremediation treatment system was implemented in 2003 to remove nitrate from <br /> groundwater, uptake nitrogen from soil, and degrade pesticide and herbicide compounds. Soil <br /> sampling was initiated to monitor the effects of phytoremediation on soil constituents. Pursuant <br /> to a letter dated 22 January 2008 by Central Valley Water Board staff, OxyChem discontinued <br /> sampling for pesticides and herbicides, because the concentration of these compounds were <br /> below cleanup goals. OxyChem may be required to resample soil for organic constituents prior <br /> to considering the site for no further action. <br /> The fall 2011 sampling data show that nitrogen still exceeds cleanup goals in many locations. <br /> Therefore, OxyChem needs to continue sampling for nitrogen compounds. However, the <br /> KARL E. LONOLEY ScD, P,E..CHAIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFXXpER <br /> 11020 Sun Cenler Drive 0200 Rancho Cordova.CA 95010 1 www walerboarbs cagoy/camrmvaVi y <br />