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M. Scott Mansholt - 5 - 11 March 2008 TAOC Tracy Gravel Pits approximately 400-feet to the northwest, appears to be located on the Georgia-Pacific property adjacent to the west. DWR records indicate the well is 75-feet deep and screened at 40 to 60-feet. We requested that this well be sampled since prior boring GMX-24 located nearby in the northwest corner of the gravel pits site previously reported 770 pg/L TPHd in groundwater at that location. Considering the wells location, depth, and screen interval an additional effort needs to be conducted to gain access to this well for sampling and testing. However, in lieu of additional sampling and analysis, if it is determined that recent analytical results are available from another source, this information may be submitted. SUMMARY Downgradient groundwater samples, ND for TPH compounds, indicates the lateral extent of affected groundwater is limited in extent and has been adequately defined along the northern property boundary. The results suggest that affected groundwater has not migrated offsite to the north. Analysis of samples for general minerals reported total dissolved solids (TDS) exceeded the water quality objective of 3,000 mg/L in five of the nine groundwater samples (3,000, 3,900, 5,000, 14,000, and 27,000 mg/L). This data indicates the uppermost shallow groundwater of the area is impaired for reasons not related to prior site activities. The data search for wells near the site indicates there are several wells present but none within the search radius are directly downgradient or upgradient. The majority of the wells had an adequate sanitary surface seal and/or was of sufficient distance and direction to be protective of shallow groundwater. Additionally, the downgradient extent of affected groundwater is limited to onsite and based on the findings appears not to have migrated offsite. Soil samples and observations from borings and excavations suggest that petroleum hydrocarbon compounds have not significantly affected soil within the southwest one-third portion of the site, south-southwest of the gravel pits; additional investigations are not needed for this part of the site. Elevated TPH concentrations in soil ar:d visual observations were found primarily on the north- northeast portion of the site from the gravel excavation north to the property boundary. Affected soil occurs in distinct thin layers at specific depths generally in the upper 11-feet. The vertical extent of affected soil at approximately 11-feet and coincides with prior investigations. Soil samples obtained from beneath the distinct asphaltic layers are ND for TPH compounds; below these layers affected soil was not observed. Hard, nodular asphaltic material to 6-inches diameter brea identified on the surface and in the upper few feet, appears to be residual TPH material derived from tank bottoms/crude oil deposited in the former shallow sumps/ponds. This material has weathered and dried out and was likely exposed on the surface/near surface by weed control tilling activities.