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Report of Findings—Phase H Soil anu ;roundwater Assessment Page 3 Teixeira-Souza Dairy February 1,2007 WKA No.6504.45 Once finalized, the new tentative WDR document will be the most comprehensive operations and monitoring guidance for dairies to date. Additions to the updated WDR guidance, in comparison to previous WDRs, include a comprehensive periodic soil sampling program to monitor impacts to soils at dairy facilities. In anticipation of the tentative WDR document's approval and implementation by the RWQCB, WKA developed a scope of work for this assessment of soil and groundwater conditions at the site to incorporate key sampling requirements to meet the tentative WDR. FIELD ACTIVITIES On December 27 and 28, 2006, WKA field representatives directed the drilling and sampling of twenty direct-push borings (SB 1 through SB20)to profile current soil and groundwater conditions at various locations across the site (Figure 2). V&W Drilling of Isleton, California, provided a truck-mounted GeoProbe drilling rig for both days of sampling activities, while RST Drilling of Woodland, California provided a track-mounted GeoProbe drilling rig for the second day of sampling activities. The track-mounted GeoProbe drilling rig was added, as the western portion of the site was rendered inaccessible to the truck-mounted GeoProbe rig clue to saturated ground conditions resulting from recent winter storm events. The twenty boring locations were advanced to depths ranging from 20 to 24 feet below ground surface (bgs), depending on local soil conditions and the depth that groundwater was first encountered. Soil samples were collected from various depth intervals at each boring location at depths ranging from 1 to 14 feet bgs for lithologic observation and/or chemical analysis. Soil samples were taken from the acetate tube lining used in the GeoProbe drill stem and field screened for methane using a RKI Eagle landfill gas analyzer, then collected into eight-ounce glass jars with Teflon-sealed lids. Soil samples were promptly labeled and placed into an ice-chilled cooler for transport to the analytical laboratory under chain-of-custody documentation. Ten of the 33 soil samples collected over the two-day sampling event were chosen for laboratory analysis,the remaining 23 soil samples were held by the laboratory. All sampling equipment was decontaminated with a soap solution of AlconoxTM and rinsed in clean, potable water prior to collecting each sample. Groundwater samples were collected after placing a '/4-inch PVC casing into each borehole, with the bottom part of the casings screened to allow for groundwater to collect into the borehole. A plastic hose with check valve was used to collect water samples in the boreholes advanced by the truck-mounted GeoProbe rig while a peristaltic pump was used to collect water samples from the � ;.V