ARCHIVED REPORTS_2010 ANNUAL REPORT

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Nestle USA, Inc., Ripon, California March 31, 2011 2010 Annual Report within the Study Area where modeling results indicate that a pumping well, or the presence of a vertical conduit between aquifers, could negatively influence the movement of current plume boundaries. 2.7 STOCKTON AVENUE GROUNDWATER EXTRACTION AND TREATMENT SYSTEM SHUTDOWN Nestle installed the Stockton Avenue groundwater extraction and treatment system (the Off-site extraction and treatment system) in 1999 at 519 South Stockton Avenue in Ripon, California. Extraction well E-2 was screened to address TCE concentrations in the B-zone of the Upper Aquifer. Nestle added extraction well E-6 in 2004 to address TCE and its daughter products reported in groundwater samples from the Intermediate Aquifer. Nestle documented the decline in the performance of the Stockton Avenue extraction and treatment system and the decline in the VOC removal rates in a shutdown request submitted to the RWQCB on November 5, 20096. In response, the RWQCB directed ECM: • To install new wells to confirm that the concentrations of TCE and other COCs resulting from a sewer line leak have been sufficiently reduced in the B-zone (Upper Aquifer) at Stockton Avenue, and • To verify the Site Conceptual Model's (SCM) conclusion that the concentrations of TCE and other COCs within the C-zone (Intermediate Aquifer) at Stockton Avenue result from migration from the City of Ripon sewage treatment ponds near the Stanislaus River. Accordingly, ECM installed two B-zone wells at Stockton Avenue, and one C-zone well on Fifth Street, which is located south of Stockton Avenue between Stockton Avenue and the City of Ripon WWTP ponds'. Results from groundwater samples collected from wells M-52B and M- 53B indicate that the Stockton Avenue Treatment System has been successfully remediating the target area surrounding this location. Groundwater sample results from well M-54C support the findings of the SCM that there is no Intermediate Aquifer source of CDCs beneath the area of 519 South Stockton Avenue. Nestle requested permission to shut down the Stockton Avenue extraction and treatment system$. The RWQCB concurred and ECM ceased system operation on October 1, 2010. 2.8 VAPOR EXTRACTION WELL CLOSURE In December 2009, ECM decommissioned eight VE wells (VE-1 through VE-3, VE-5 through VE-7, VE-9, and VE-10) that were located at the former Nestle facility at 230 Industrial Avenue. A ninth VE well (VE-8)was decommissioned at the property located at 519 South Stockton Avenue. ECM was unable to locate three wells (VE-4, VE-11 and VE-12) in December 2009. A ground penetrating radar (GPR) survey conducted by Subtronic Corporation (Subtronic) in February 2010 identified shallow anomalies in the vicinity of the surface survey points for wells VE-11 and VE-12. In December 2010, ECM excavated a 5-foot by 5-foot area to a depth of approximately four feet around the survey location of each well and was able to locate wells VE-11 and VE-12. Well VE-4 was not located during any field reconnaissance, including the excavation completed in December 2010. ECM completed the proper decommissioning of wells VE-11 and VE-12 on January 14, 2011, and submitted documentation for all field work associated with the VE wells to the San Joaquin County Environmental Health Department (SJCEHD) on January 24, 2011. SJCEHD issued a letter on February 1, 201110 confirming that no further work was required for VE-4 and that all field work associated with these wells had been satisfactorily completed. 6