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Hydropunch groundwater sample obtained from Boring 2-2 (Backfilled UST Excavation). No other hydrocarbons were detected in the groundwater samples obtained from the UST area. However, Unidentified Extractable Hydrocarbons (C1) to C30) was detected in the Hydropunch groundwater sample from the soil boring located adjacent/downgradient to the shop leachfield at a concentration of 330 µg/L. The results of the soil and groundwater sampling were detailed in Kleinfelder's February 24, 1997 report titled "Limited Phase II Soil and Groundwater Assessment, Farmhouse Area....". While in the process of trying to obtain regulatory closure on this area, it was recommended that additional borings be advanced and both water and soil be sampled for BTEX, TPH-G and Oxygenates. On September 8 and September 9, 1997, soil and Hydropunch II® water samples were obtained from two soil borings (Borings 2-2A and 2-2B) advanced in the vicinity of the former UST. The borings were advanced in the vicinity of the December 1996 underground storage tank (UST) boring (Boring 2-2) which yielded detections. The September 8 and 9, 1997, sampling of boring 2-2A and 2-213 revealed no detectable hydrocarbons. In a report dated October 14, 1997, it was concluded that the resampling suggested that the trace level detected in the one groundwater sample obtained in December 1996 may have been field or laboratory cross contamination. This was further supported by the lack of any detectable soil contamination during either sampling event (December 1996 or September 1997). It was further concluded that even if the 0.51 lig/L of toluene were to actually have existed, its extent would be very limited and the concentrations were up to three orders of magnitude below drinking water standards. Therefore, no threat to groundwater resources, the environment or human health existed. Based on the above detailed findings, Kleinfelder recommended no further investigation or clean-up and that this data be submitted to PHS/EHD to be used to support regulatory closure of the former farmhouse UST which was removed in the late 1980's. Additionally, I understand that there may be some concern regarding the 330 gg/L of Unidentified Extractable Hydrocarbons (UEHs) in the C10 to C30 hydrocarbon range detected in the groundwater sample from Hydropunch location 2-4. Please note that the UEHs detected were related to the leachfield for the septic system for the restroom located off the shop building. The lateral extent of the hydrocarbons in groundwater is limited to less than approximately 100 feet downgradient, as evidenced by the lack of UEHs in the groundwater samples obtained from Hydropunch locations 2-5 and 2-6. Based on the limited extent, the low concentrations of contaminants detected in the septic system area, and the lack of potential receptors, the San Joaquin County PHS/EHD granted closure on all but the UST in this area through the SB 1248 process. Therefore, based on all of the above, it is Kleinfelder's opinion that no further investigation or cleanup is warranted as it relates to the former underground storage tank at the former farmhouse area. As such, Kleinfelder again requests on behalf of Atherton Kirk Development Company that closure be issued on the UST. 20-3978-03.WS0/20181,839 Page 2 of 3 Copyright 1998,Kleinfelder,Inc. October 12, 1998 KLEINFELDER 2825 East Myrtle Street,Stockton,CA 95205-4794 (209)948-1345 (209)948-0621 fax