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I. of 10 mg/l. PMCL's are derived from health based criteria (by California Depaftment of Health Services from public health goals from one in a million [101 incremental cancer risk estimates for carcinogens and threshold toxicity levels for non-carcinogens. The relatively high concentrations of TKN in the soils may be an indicator of a possible source of the nitrate as NO3 and total nitrogen concentrations noted in the groundwater sample. In MW-2 the concentrations of the fertilizer constituents showed a decreasing trend with depth in the boring. The reduction ranged from >55% (phosphate) to >88% (ammonia as N) from 1-foot to 10-foot. The soils encountered in MW-2 were noted as showing some of the highest concentrations of ammonia as N, nitrate as NO3, total nitrogen, nitrate+nitrite (N), TKN, and phosphate compared to the other soil borings advanced for MW-1 or MW-3. MW-2 is located on the northern boundary of the site and downgradient of approximately 1/4 of the site where vehicles were parked in the past and in close proximity of the tank washout pad/sump. The groundwater sample in MW-3 showed no concentrations at or above the applicable WQGs for the fertilizer constituents, but it should be noted that TKN concentrations in MW-3 may be a potential source for nitrates in water. The soil samples collected from MW-3 also showed decreasing concentrations with depth in the 1-foot and 5-foot samples analyzed. (The 10-foot sample was not analyzed and put on hold). As seen in the other sample locations discussed the concentrations decreased by up to >60% (nitrate as NO3). It should be noted that MW-3 is located near the sites northwest boundary and downgradient to the site. Additionally, this portion of the site has been paved and had not been noted from Kleinfelder's Phase I report as having typical operations such as storage or mixing of chemicals in this portion of the site. Concentrations of the fertilizer constituents found in MW-3 may be indicative of naturally occurring conditions. The water sample collected from the domestic well on site showed no detectable concentrations of ammonia as N, TKN, and phosphate. The detected concentrations of nitrate as NO3 and total nitrogen poses a risk due to the elevated concentrations seen in the sample. The nitrate as NO3 concentration (209 mg/1) and total nitrogen (47 mg/1) exceeds the MCLs of 45 mg/1 and 10 mg/1 respectively. There may be an offsite source of these constituents or an existing background condition as the domestic well is from a deeper portion of the aquifer. There was also detections of 1,2-Dichloropropane and 1,2,3-Trichloropropane in the domestic water supply well. The 1,2- Dichloropropane concentration was 0.049 mg/1, above the PMCL of 0.005 mg/l. The concentration of 1,2,3-Trichloropropane was 0.004 mg/1, below the MCL of 0.042 mg/l. As referenced from the "Handbook of Environmental Data on Organic Chemicals", Edition, by Verschueren; 1,2-Dichloropropane has been used in fumigants and as an anti-knock lead scavenger. The biological effects for humans is mild skin irritation. The extent or source for these compounds are unknown at this time, and may be present due to an off site source as neither compound was detected in the shallow soil samples collected at the site or from the shallow groundwater samples. The four groundwater samples collected at the site showed no detectable concentrations of DBCP at or above the laboratory reporting limits. There was however, one detection of EDB in MW-2 with a concentration of 0.04 ugh, below the MCL. The MCL for EDB is 0.05 ug/l. It should be noted again that no concentrations of EDB were detected at or above the laboratory reporting limit 27125.E01 / STO4R181 Page 20 of 23 0 2004 Kleinfelder, Inc. February 13, 2004 KLEINFELDER 2825 East Myrtle Street, Stockton, CA 95205-4794 (209) 948-1345 (209) 948-0621 fax