Laserfiche WebLink
Ms. Vicki McCartney Project No. 8800401A.0201 <br /> October 26, 2004 <br /> Page 6 <br /> Shaw recommends that the, cleanup level goals for this site be the California <br /> Department of Health Services Primary MCLS, which are 13 pg/l for MtBE, <br /> 1.0 µg/1 for benzene, 150 pg/l for toluene, 300 µg/l for ethylbenzene, and. <br /> 1,750 pg/l for xylenes. Primary MCLS have not been established for TPHg. ' <br /> ■ Cross sections based upon boreholes monitoring wells, trenches, and supporting <br /> geological mapping logs. <br /> Figures 6 and 7 illustrate the lithology encountered beneath the site during <br /> previous investigations and the approximate vertical and lateral extent of impact <br /> to groundwater as defined by MtBE to 5 pg/l. Appendix D includes boring logs <br /> showing soil encountered beneath the site during previous investigations. <br /> A site map showing sensitive receptors (i.e. local water supply wells, buildings or <br /> ` utilities impacted or potentially threatened). <br /> k j Figures 1 and 2 show pertinent features at the site and in the vicinity. A water <br /> ,/D do <br /> supply well survey previously conducted by Shaw, indicated that no wells are ,`., <br /> located within 2,000 feet of the site. Based on the limited extent of groundwater 1"'Je_ '�1tro` <br /> impact beneath the site, no critical receptors appear to be impacted or threatened. <br /> ■ A risk assessment will be necessary to demonstrate that the site poses no <br /> unacceptable risks to human health or the environment. <br /> The hydrocarbon plume extends beneath an area that is currently being used for <br /> commercial purposes (gasoline sale) and transportation (West Hammer Lane). <br /> Most of this area is paved with asphalt or concrete. No residential buildings are <br /> located within the probable extents of the plume. No water producing wells are — tT <br /> located within 2,000 feet of the subject site. 11 <br /> i <br /> f Potential exposure receptors include current and future workers and customers of <br /> 1 the subject station at 3250 West Hammer Lane, motorists, pedestrians, and utility <br /> maintenance workers. The potential exposure mediums are ambient air and soil <br /> 1 and groundwater in potential future excavation areas. The major exposure <br /> N:IsacDP120041Pr�188018800401A.4ad.doc Shaw Environmental,Inc. <br />