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F e r <br /> i <br /> Mr. Jim,Barton <br /> h. RWQCB. <br /> March 29,2013 <br /> Page 15 <br /> Strict chain-of-custody protocols will be followed throughout all sample transfers. Chain- <br /> of-custody procedures provide an accurate written record tracing the possession of <br /> individual samples from the time of field collection through laboratory analysis. The <br /> chain-of-custody record will document the samples collected and the analyses requested. <br /> Sample Analyses <br /> URS' procurement process includes confirming the laboratory chosen is Environmental <br /> Laboratory Accreditation Program/National Environmental Laboratory Accreditation <br /> Program certified for each analytical method needed. All groundwater and soil samples <br /> will be analyzed for TPHg and VOCs using EPA Method SW826013. <br /> Soil vapor samples will be analyzed for TPH and VOCs using MethodTO15. Samples <br /> collected will be analyzed on a standard 10-day turnaround time. One soil gas sample <br /> from each of the three investigation area will also be analyzed to speciate TPH by the <br /> length of carbon chains (up to C12), for vapor intrusion risk assessment. One soil gas <br /> sample from each investigation area will also be analyzed for oxygen and carbon dioxide <br /> to assess aerobic/anaerobic conditions in the soils which may be aiding bio-degradation <br /> of TPH. <br /> Investigation Derived Waste <br /> Soil cuttings and wastewater generated during drilling and groundwater sampling <br /> activities will be placed in 55 gallon Department of Transportation approved steel drums, <br /> pending disposal. Following receipt of analytical results,, waste drums will be transported <br /> to an approved facility for disposal. <br /> Assessment Report and Risk Assessment <br /> A report will be prepared summarizing field activities, the results of soil gas, soil and _ <br /> groundwater sampling, and our conclusions and recommendations. Included in the report <br /> will be an updated CSM that will address the comments and recommendations presented <br /> in the February 27, 2013, RWQCB letter. The report will also include a screening-level <br /> human health risk assessment prepared by the URS project risk assessor. <br /> The screening-level human health risk assessment will be performed using the soil vapor <br /> and soil data collected from the site. The vapor intrusion assessment will be in <br /> accordance with recent DTSC (2011a,b) guidance. The characterization of risk to <br /> construction-worker receptors will be performed in general conformance with the DTSC <br /> (1994) Preliminary Endangerment Assessment process, including incorporation of more- <br /> recent methodological changes in risk assessment (e.g., addressing dermal exposures <br /> [EPA, 20041 and inhalation exposures [EPA, 2009]), current toxicity factors, and other <br /> procedural recommendations (DTSC, 2011c,d). <br />