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. WORK PLAN FOR CONSTRUCTION OF <br /> TWO OFF-SITE GROUNDWATER MONITORING WELLS ATR-13 AND ATR-14 <br /> FOR ARCO FACILITY 2093, TRACY, CALIFORNIA <br /> This work plan has been prepared by Brown and Caldwell on behalf of ARCO Products <br /> Company (ARCO) The proposed scope of work is to install two off-site groundwater <br /> monitoring wells ATR-13 and ATR-14 in the vicinity of ARCO Facility 2093, located at 3425 <br /> Tracy Boulevard Tracy, California The purpose of the wells will be to define the extent of <br /> hydrocarbons in the downgradient direction of existing groundwater monitoring well ATR-8 <br /> in which tree product has been identified Figure 1 is a vicinity map showing the location of <br /> ARCO Facility 2093 Figure 2 is a site map presenting the proposed locations of the off-site <br /> groundwater monitoring wells The work plan will be submitted to ARCO, the San Joaquin <br /> County Public Health Services, Environmental Health Division (County), and the California <br /> Regional Water Quality Control Board (Regional Board) The proper well installation permits <br /> will be obtained prior to constructing the oft-site groundwater monitoring wells A Site Safety <br /> and Health Plan (SSHP) has been prepared for this site and will be implemented and retained <br /> on-site during the field work <br /> This work plan describes the methods to be used in the field to construct the off-site <br /> groundwater monitoring wells This plan proposes a protect schedule for work at the site and <br /> the timely submittal of a site summary report to the County and RWQCB after the completion <br /> of this work <br /> PURPOSE <br /> Free hydrocarbons have been identified in off site groundwater monitoring well ATR-8 Well <br /> ATR-8 is located off site to the north of the ARCO Facility as indicated on Figure 2 The <br /> source of the free hydrocarbons in well ATR-8 was unknown upon its discovery because <br /> hydrocarbons were not identified or identified in minor concentrations in the two down <br /> gradient wells (ATR-1 and ATR-2) on the ARCO facility ARCO subsequently installed an <br /> additional groundwater monitoring well (SMW-1) on the north side of the ARCO Facility and <br /> confirmed the presence of dissolved phase hydrocarbons on the north side of the Facility In <br /> addition, ARCO sampled and analyzed the free phase hydrocarbons from well ATR-8 and <br /> dissolved phase hydrocarbons from well ATR-3 and SMW-1 The results of the sampling <br /> indicated that the hydrocarbons identified in wells ATR-3 and SMW-1 were most likely from <br /> the same source as the free hydrocarbons in well ATR-8 <br /> This report was prepared in accordance with the standards of the environmental consulting cnduslry at the time it was <br />. prepared It should not be relied upon by parties other than those for whom it was prepared, and then only to the <br /> extent of the scope of work which was authorized This report does not guarantee that no additional environmental <br /> contamination beyond that described in this report exists at the site <br /> 26404ZEPORTS\WORK PLAN <br />