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Limited Subsurface Investigation Report— City of Ripon / Madsen Sunrise Dairy, Ripon, California September 30, 2010 3.2 Groundwater Sampling After groundwater was encountered, probing was halted and poly -vinyl choride (PVC) casings were temporarily installed in the borings to facilitate groundwater sample collection. Grab groundwater samples were collected from each boring with a clean stainless steel bailer. The samples were decanted into the appropriate laboratory -supplied containers, as described in GR's Field Methods and Procedures (Appendix A). 3.3 Borehole Sealing After probing and sampling were completed, the boreholes were sealed with neat cement gout. The gout was placed from the bottom of the borehole to approximately one foot bgs using the temporary casings as removable tremie pipes. The boreholes were finished to surface with the original surface material. Ms. Lori Duncan of the SJCEHD was present to observe the grouting procedures. 3.5 Laboratory Analysis All soil and groundwater samples were submitted to KilTAnalytical in Davis, California (NELAP #08263CA). The samples were analyzed for Total Petroleum Hydrocarbons as gasoline (TPHg) by Environmental Protection Agency (EPA) Method 8260B, and Total Petroleum Hydrocarbons as diesel (TPHd) by EPA Method 8015 modified. Copies of the laboratory analytical reports, chromatograms and chain -of -custody records are included in Appendix C. 4.0 RESULTS 4.1 Subsurface Conditions Detailed descriptions of the lithology encountered during this investigation are presented on the boring logs in Appendix B. In Geoprobes GP -1 through GP -3, materials encountered during probing consisted of sand and gravel fill at the surface followed by silty sand to depths ranging from 5 to 5.75 feet bgs. Underlying the silty sand are interbedded silts and sands extending to depths ranging between 25.75 to 27 feet bgs, which are in turn underlain by well graded sand to the total depth explored (32 feet bgs). In GP -4, artificial fill consisting of silty sand with gravel and debris was encountered beneath the surface fill and extended to approximately 10 feet bgs. This fill was underlain by silty sand mixed with silt, interpreted as fill and disturbed native soil, to a depth of 12 feet bgs. Interbedded silts and sands extend from 12 to 26 feet .bgs and are underlain by well graded sand to 32 feet bgs in GP4, similar to the lithology encountered in GP -1 through GP -3. Groundwater was encountered during probing at approximately 29 to 29.5 feet bgs. 4.2 Soil Analytical Results Soil samples collected from Geoprobes GP -1 through GP4 did not contain detectable concentrations of TPHg. Soil samples from GP -3 showed no detectable concentrations of TPHd. Soil samples from GP -1 and GP -2 contained no detectable concentrations or TPHd, except for soil sample GP -1-5, collected at a depth of fivefeet bgs, which contained 1.4 ppm diesel (reported by the lab to be higher boiling point hydrocarbons than diesel) and sample GP -2-25, collected ata depth of 25 feet bgs, which also contained 1.4 ppm diesel (reported by the lab to contain discrete peaks and higher boiling point hydrocarbons than diesel). 25-948223.1-3