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1 <br />11 <br />1 <br />1] <br />1 <br />Section 6 <br />RESULTS <br />SUBSURFACE <br />The soils underlying the McMullin Gas Dehydrator Station include interbedded layers of silt and sand (see <br />the Boring Logs in Appendix A and the Geologic Cross Sections, Figure 7). The interbedded nature of this <br />soils is typical of fluvial depositional systems. <br />Groundwater was encountered in the boreholes at depths ranging from 11 to 13 feet. No site specific <br />information is available regarding the direction of groundwater flow; however, the regional groundwater <br />flow direction is to the west-northwest (San Joaquin County Flood Control District, Fall 1973). <br />CHEMICAL ANALYTICAL RESULTS <br />Soil Samples <br />Table 2 summarizes the results of the laboratory analyses performed on the soil samples collected from the <br />boreholes. The formal laboratory reports and chain -of -custody records are presented in Appendix B. <br />Petroleum hydrocarbons were reported in soil samples collected from four of the boreholes at the site (B-1, <br />B-2, B-3 and B-9), primarily from the capillary fringe at a depth of 12%: feet. The highest levels of <br />petroleum hydrocarbons were reported from the 12%: -ft sample collected from B-3. This soil sample <br />contained TPH-G (880 mg/kg), TPH-K (640 mg/kg), benzene (1.3 mg/kg), toluene (2.1 mg/kg), <br />ethylbenzene (24 mg/kg) and xylenes (35 mg/kg). <br />The petroleum hydrocarbons identified in these samples consist primarily of gasoline and kerosene -range <br />hydrocarbons. Diesel -range hydrocarbons were identified in only one sample (B-9 at 0.5 to 3.0 ft), and <br />none of the samples contained detectable levels of total petroleum hydrocarbons as motor oil or total oil and <br />' grease. <br />[1 <br />1 <br />1 <br />Water Supply Well Samples <br />Table 3 summarizes the results of the laboratory analyses performed on the water samples collected from <br />Hofinan Well No. 5, located about 200 feet east of the dehydrator station. The formal laboratory reports <br />and chain -of -custody records are presented in Appendix B. <br />A minor concentration of diesel -range hydrocarbons (160 µg/l) was detected in the water sample collected <br />on April 27, 1993; no other analytes were detected in the sample. Additional samples were collected on <br />June 18, 1993, both upstream and downstream of the pressure tank, and the laboratory reports indicate that <br />cca08/19/93(9660a.doc/cp43) 6-1 <br />