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Report of Findings—Dairy Waste Removal Page 4 Teixeira—Souza Dairy November 27,2006 WKA No. 6504.07 Soil Gas, Soil, and Groundwater Investigation To evaluate the effectiveness of the waste removal activities and to screen for the potential presence of hazardous gases, soil gas, soil, and groundwater samples were collected from the areas identified as having the largest amounts of impacted soil, waste, manure, or sludge. Boring and sample locations associated with the investigation are shown on Figure 2. Analytical results are presented in Table 1. Sampling Activities A truck-mounted GeoProbe® boring system was utilized to collect soil and soil gas vapor samples at depths ranging from three to five feet below the existing ground surface, or just immediately above the groundwater level. A total of 10 locations were sampled for soil, however, only six yielded soil gas samples. The limitation with soil gas sample collection was due to shallow groundwater or dense soils. The six soil gas vapor samples were collected from the footprint of the barn, corrals, waste stockpile, and adjacent to the wastewater ponds. All soil gas samples were collected in Tedlar® bags and placed in an opaque, sealed container to prevent exposure to sunlight, and promptly submitted under chain-of-custody to Air Toxics, Limited, in Folsom, California for analysis. The six soil gas samples were analyzed for methane and hydrogen sulfide,the two most common soil gas vapors that originate from subsurface decaying organic matter, using EPA Methods 1946 and 5504, respectively. Ten soil samples, one from each boring at the corresponding gas sample depth, were collected from the plastic liners obtained from the GeoProbe®boring system (Table 1, Figure 2). The soil samples were placed into nine-ounce glass jars with Teflon®-sealed lids, placed in an ice-chilled cooler, and submitted under chain-of-custody to California Laboratory Services, a California Department of Health Services accredited laboratory, for analysis. The soil samples were analyzed for methane, ammonia(as nitrogen), and hydrogen sulfide using EPA Methods 1946, 350M, and 5504, respectively. Five groundwater samples were collected from across the site. Three of the samples were collected from groundwater encountered in borings ST-1, P2-1, and P2-2 (Figure 2). These three samples were collected using a clean plastic bailer. The two remaining samples were collected from the groundwater encountered in Pond 1 by immersing the sample containers below the water surface. The samples were placed in an ice-chilled cooler and submitted under chain-of- custody to California Laboratory Services for analysis. The water samples were analyzed for methane, ammonia(as nitrogen), and hydrogen sulfide using EPA Methods 1946, 350M, and 5504, respectively.