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Shell Site Investigation Report <br /> Executive Summary <br /> • In May 2014, ENGEO conducted a geotechnical investigation for Medline within a portion of the <br /> Cordes Ranch site related to the Cordes Ranch Development Plan. CRA observed ENGEO drilling <br /> activities near the former pipelines and collected soil samples for chemical analysis from fourteen <br /> geotechnical borings that were nearest to the former pipelines. TPHc and BTEX were non-detect in <br /> all soil samples except for at detection of TPHc at 27 mg/kg in sample 1-BO7 at 15 fbg. These results <br /> are consistent with historical soil analytical data that indicate crude oil impact in soil is limited to <br /> isolated locations and does not extend far laterally from the former pipelines. <br /> • Three borings(B-117 through B-119)were advanced in lune 2014 to delineate crude oil impact in <br /> soil near well MW-15. Based on the soil sample analytical results, crude oil impact in soil near <br /> MW-15 is delineated lateral to the former pipelines by B-117 to the southwest and B-119 to the <br /> northeast. Crude oil impact in soil near MW-15 is delineated along the pipeline alignment to the <br /> southeast by previously installed soil boring B-80. However,delineation to the northwest of MW-15 <br /> along the pipeline alignment was not achieved by advancement of boring B-118 (see Figure 4). <br /> TPHc, benzene,ethylbenzene,and xylenes were detected in samples from this boring at various <br /> depths. Advancement of a step-out boring to the northwest could not be conducted since access to <br /> the adjacent property was not granted.Vertical delineation of soil impact is also complete given that <br /> the borings were advanced to groundwater. <br /> • Monitoring well MW-16 was installed in June 2014 to delineate crude oil impact east of soil boring <br /> B-109. The soil sample and groundwater sample analytical results from MW-16 provide lateral <br /> delineation to the east for crude oil impacts detected at boring B-109. Delineation southeast of <br /> B-109 could not be completed due to the presence of Hansen Road and because access to the <br /> property southeast of B-109 was denied. <br /> • All monitoring wells(sans MW-16) and vapor probes were properly destroyed in support of the <br /> pending land development and in compliance with the requirements of the San Joaquin County <br /> Environmental Health Department. <br /> • CRA recommends monitoring groundwater at MW-16 on a quarterly basis for one hydrologic cycle, <br /> after which the monitoring frequency will be re-assessed. <br /> • CRA does not recommend any other activity in consideration of the remedial excavation work that is <br /> currently underway. <br /> CCICONESTOGA-ROVERS <br /> OS0223 <br /> y &ASSOATES i35i <br /> September 2014 i <br />