ARCHIVED REPORTS_MONITORING WELL M-10 INVESTIGATION REPORT 2010

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M-10A Investigation Report November 30, 2010 Nestle USA, Inc., Ripon, California Corporation (TestAmerica) for laboratory analysis on an expedited turn-around time for volatile organic compounds (VOCs), in accordance with Environmental Protection Agency (EPA) Method 8260B. 3.4 DECONTAMINATION After each use, all drive rods and other reusable components were cleaned to prevent cross contamination. The drillers cleaned all reusable equipment with a non-phosphate detergent and used a steam cleaner as a final rinse. Only clean drill rod was used in each boring. 3.5 INVESTIGATION DERIVED WASTE CPT drilling does not produce any soil waste. Minimal wastewater was produced during decontamination procedures and sampling procedures. ECM drummed all wastewater for treatment through the on-site carbon treatment system prior to discharge to the City of Ripon sewer system. 4 INVESTIGATION RESULTS ECM commenced drilling and sampling work on September 15, 2010 and completed the work on October 1, 2010. ECM completed subsurface lithology and groundwater investigation activities at 14 CPT boring locations, collecting a total of 41 groundwater grab samples for VOC analysis. All samples were collected from depths between 58 feet bgs and 110 feet bgs, varying at each boring location. 4.1 BOREHOLE LITHOLOGY During the field investigation, ECM personnel inspected the field CPT logs and created geologic cross-sections (Figure 4, Figure 5, and Figure 6) to identify coarse-grained transmissive intervals for groundwater sample collection. ECM observed coarse-grained units to be generally continuous between about 30 and 40 feet bgs, 50 and 75 feet bgs, and 80 and 115 feet bgs. The shallow lithology from 0 to 50 feet bgs consisted of interbedded sands, silts, and clays characteristic of river channel and flood plain deposits. Below this, from 50 feet bgs to the total investigation depth of 120 feet bgs, discontinuous lenticular clays and silt lenses interbedded with sands and sand-rich silts and clays were observed, and these soil types have been interpreted as fluvial and alluvial fan deposits. The geologic cross sections presented in Figure 4, Figure 5, and Figure 6, illustrate how the lithology is highly heterogeneous and likely interconnected. An interpretation of the lithology and the concentrations observed at specific depth intervals is provided in Section 5. The boring logs for the CPT boreholes are included in Appendix B. 4.2 LABORATORY RESULTS TestAmerica, a California-certified environmental laboratory, analyzed the groundwater samples for volatile organic compounds (VOCs) in accordance with EPA Method 8260B. The laboratory results are summarized in Table 1 and the reports are included in Appendix C. 6