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19 • TPH as gas, diesel and motor oil were detected in the ground water sample from B4. No BTEX was detected. Naphthalene was qualitatively identified. Alternatives for Site Mitigation As a result of the above findings, it is apparent that additional site characterization is necessary to identify the extent of soil and ground-water contamination. Additional characterization is particularly needed in the vicinity of boring B4 on the western portion of the parcel. Based on the available data, some preliminary alternatives for site mitigation have been considered. On the eastern portion of the parcel, site contamination resulting from past land use activities appears to be limited to the shallow soil; petroleum hydrocarbons and elevated metal concentrations are present at depths of generally less than 5 feet. Available data further indicate that site conditions are conducive to attenuation of contaminants in the shallow soil horizon. The above discussed contaminants have not been detected in ground water which is present at a depth of approximately 25 feet. Extrapolation of soil pH and soluble lead concentration data from boring B4 suggest low mobility of the lead compounds in soil; therefore, actions to promote stabilization via in- situ or ex-situ treatment of the soil would not be expected to enhance site mitigation. At this time, two alternatives appear to be appropriate for addressing soil contamination on the eastern portion of the parcel. These include 1) no action, i.e. leave the soil in place and 2) excavation and disposal of the soil off-site. If the soil is left in place, additional site characterization will need to be conducted in order to request closure of the site with contaminants remaining in place. If the RWQCB concurs that the remaining contaminants do not present a health or environmental threat, N conditional closure of the site may be approved.