ARCHIVED REPORTS XR0006617 - Laserfiche WebLink

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Updated Corrective Action Plan—Tosco(76)Service Station No 11192, Stockton, California June 26,2002 FEASIBILITY STUDY (Continued) 1 For all sites,each recommended alternative shall be designed to mitigate nuisance conditions and risk of fire or explosion: A site Health and Safety Plan (HSP) will be prepared for the recommended scope of work The HSP will be strictly followed in order to ensure site and community safety 2 For sites where unauthorized release affects or threatens water with current or potential beneficial uses designated in water quality control plans, the feasibility study shall also identify and evaluate at least two alternatives for restoring or protecting these beneficial uses: As previously stated in this CAP, it does not appear that the hydrocarbons that are present at the subject site threaten any surface water or wetlands in the vicinity of the site that have a current or potential beneficial use However, the groundwater in the vicinity of the site has been classified by the RWQCB as an area of current and/or potential beneficial use Therefore, GR recommends installation of an ozone microsparge system to remediate the impacted groundwater beneath the site The existing groundwater monitoring wells are currently monitored and sampled quarterly This program will be continued and modified,as appropriate,to provide verification monitoring of corrective action effectiveness and progress towards cleanup levels + 33 _ Cleanup Levels Cleanup levels for ground or surface waters, affected or threatened by the unauthorized release, shall meet the following requirements (i) For waters with current or potential beneficial uses for which numerical objectives have been designated in water quality control plans, the responsible party shall propose at least two alternatives to achieve these numerical objectives. (it) For waters with current or potential beneficial uses for which no numerical objectives have been designated in water quality control plans, the responsible party shall recommend target cleanup levels for long-term corrective actions to the regulatory agency for concurrence. Final cleanup level goals for hydrocarbon constituents are proposed to be the California Department of Health Services Maximum Contaminant Levels (MCLs), which are 13 ppb for MtBE, 10 ppb for benzene, 150 ppb for toluene, 700 ppb for ethylbenzene, and 1,750 ppb for xylenes If these levels are not achievable, then Tosco will work with the PHS-EHD to determine acceptable final cleanup goals 140245 08 12