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I since July 1996. This study indicated that the historical decreases in TPH concentrations in groundwater provide evidence that natural attenuation of these compounds has occurred and is occurring at the site. However, the reported results of inorganic analyses and water quality parameters were inconclusive in suggesting whether electron acceptors such as nitrate and sulfate are available and being utilized within the petroleum hydrocarbon plume in groundwater(URS, 2000). During the Second Quarter 2000, the groundwater monitoring event included the use of Kabis sampling, which is a method for discreet sampling. Results-associated with standard sampling 9 99/1-1methods reported TPHg and benzene for two wells at concentrations of 2,000 and 20 I �� respectively. Results of Kabis samples collected at depths between 17 and 20 m (57 and 65 ft) bgs from the same two wells yielded maximum TPHg and benzene concentrations of 3,000 and 980 µg/l, respectively. TPH-d and MTBE were not detected in any of the groundwater samples. I In November 2000, while removing old surface and subgrade for repaving at the site, Caltrans and construction personnel noted discolored and odorous soil. Nineteen soil samples were collected at a depth of 0.5 m (1.5 ft)bgs over approximately 232s.quare m (2,500 square ft). Soil 1. samples were also obtained in three locations at 1.2 m (4 ft)bgs to confirm the contaminants did not penetrate below 0.6 m (2.0 ft) from an onsite stockpile. .One sample with a reported lead concentration of 1,800 mg/kg was later concluded to be anoimalous. Caltrans' consultant concluded that the heavy petroleum hydrocarbon impaction jwas associated with old asphalt and that the impacted soils in general were a non-hazardous waste (Professional Services Industries, 2000). In November 2001,MW-14 was abandoned, and MW-14Awas installed to a depth of 18.2 m (60 ft)bgs. A cone penetrometer(CPT) soil boring, CPT-1, was advanced to a maximum depth of 30 m (100 ft) bgs to obtain groundwater samples (Geocon, 2001). I i i1 a sa�oP-N.jsacOPM2IPRJIPJ8V8319 8V.Zab.cbc 1-3