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Mr. Robert Doss, P.E. <br /> December 26 , 1995 <br /> Page 2 <br /> assessment, are minimal. Therefore, Remedial Alternative 5 <br /> is proposed to maintaining these acceptable risks associated <br /> with soil through ground covers and other access <br /> restrictions and by reducing contaminant migration to <br /> groundwater. Section 9 fails to address the component of <br /> Remedial Alternative 5 that will maintain current exposure <br /> conditions at Site Area I, Area II, and the Hazelton Avenue <br /> Strip. A Deed restriction for property use, maintenance of <br /> ground-cover, controls for future management of site soils, <br /> and site access controls should be discussed in detail for <br /> these areas. <br /> 3 . Section 8. 1. 2 discusses components of alternative 2 <br /> (institutional controls) which includes groundwater <br /> monitoring to track groundwater quality over time. <br /> Semiannual groundwater monitoring, as proposed, may or may <br /> not be adequate to track conditions of groundwater. The <br /> groundwater monitoring schedule may be revised upon <br /> completion of the groundwater FS and groundwater Remedial <br /> Action Plan (RAP) to adequately track conditions of <br /> groundwater. <br /> 4. All nine of the Federal criteria must be used in evaluating <br /> remedial action alternatives in the FS. Section 8 .2 of the <br /> FS identifies these nine criteria, but only addresses seven <br /> and proposes to address the remaining two once the public <br /> community and supporting agency have reviewed the FS and <br /> draft RAP. Section 8 of the FS must include application of <br /> the State acceptance criteria and public acceptance in the <br /> evaluation of alternatives. <br /> 5. A supplemental soil investigation was conducted to provide <br /> additional characterization at areas where elevated levels <br /> of contaminants were detected in previous investigations, <br /> and in areas where data had not been collected. Section <br /> 3 . 1. 3 of the FS indicates results obtained from the field <br /> screening analyses did not correlate well with laboratory <br /> analytical results. Consequently, the FS only uses the <br /> laboratory results which consists of approximately 50% of <br /> all the supplemental soil samples collected. DTSC is <br /> concerned that the use of only 50% of soil supplemental <br /> sample result has resulted in data gaps remaining and thus <br /> the sampling objective not being met. Please provide a <br /> discussion on the supplemental sampling results including an <br /> evaluation of results, identification of data gaps, and <br /> applicability of results. <br /> PA.bdi <br /> PA25W.125%1 <br />