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I. areas may be a potential source for nitrate as NO3 in groundwater as seen in the nearby monitoring well MW-2. I. The results show no notable concentrations of organochlorine pesticides, fumigants, carbamates, organophosphates, metals, chlorinated hydrocarbons, volatile organic compounds, or semi-volatile compounds from the sample locations and the depths of this investigation. The concentrations of the fertilizer constituents noted from the soil samples collected from the soil borings advanced for the installation of the monitoring wells showed generally decreasing concentrations for each constituent with depth. In MW-1 total nitrogen (TKN + nitrate+nitrite), TKN, phosphate, and sulfate concentrations decreased to non-detectable concentration at or below the laboratory reporting limits; and ammonia as N and nitrate as NO3, and nitrate+nitrate (N) concentrations decreased by more than 50% from the 1-foot interval to the 10-foot interval. The soil samples collected in the boring for MW-2 also reported elevated concentrations of nitrate as NO3 and TKN relative to the other soil samples collected from MW-1 and MW-3. Coupled with the results from the shallow soil samples collected from B-1, B-7 and B-8, the area between MW-2, B-1, B-7, and B-8 is relatively small in aerial extent and may depict a localized concentration of TKN and nitrate as NO3 in soil. No concentrations of EDB were detected at or above the laboratory reporting limit in any of the soil samples collected for analyses from the monitoring well soil borings and the other shallow soil samples collected from the various portions of the site. Groundwater The groundwater sample collected from MW-1 showed concentrations of Nitrate as NO3 (86 mg/1) and nitrate as N (19.3 mg/1) above the respective Water Quality Goals (WQG) and referenced to Primary Maximum Contaminant Levels (PMCL) of 45 mg/1 and 10 mg/1 respectively. The remaining fertilizer constituents were below the respective MCLs, California State Action Levels for Drinking Water, or Suggested No Adverse Response Levels (SNARLs). Even though total nitrogen, TKN, phosphate, and sulfate were not detected in the soil sample above groundwater (10-foot), they were detected in the groundwater sample (with the exception of TKN) in MW-1. There may be an offsite source of these constituents or an existing background condition as MW-1 represents an upgradient condition at the site. The ammonia as N concentration in MW-2 (56 mg/1) exceeded the WQG State Taste and Odor Threshold/Drinking Water Health Advisories of 1.5 mg/1, and the USEPA SNARL of 30 mg/l. Taste and odor thresholds form the basis for many SMCLs and are threshold's used to translate narrative water quality objectives that prohibit adverse taste and odors in water. SNARLs are human health based criteria that were published by the National Academy of Sciences (NAS). SNARLs do'not reflect the cancer risk that may be posed by chemical exposure. SNARLs should only be used to interpret narrative water quality objectives where more recent health based criteria are absent. The nitrate as NO3 concentration in MW-2 (583 mg/1) exceeded the PMCL of 45 mg/1, and the total nitrogen (nitrate as N) concentration (190 mg/1) exceeded the PMCL for nitrate as N 27125E01 / STO4R181 Page 19 of 23 © 2004 Kleinfelder, Inc. February 13, 2004 KLEINFELDER 2825 East Myrtle Street, Stockton, CA 95205-4794 (209) 948-1345 (209) 948-0621 fax