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C. Dean Hubbard <br /> October 13, 2006 <br /> Page 2 <br /> Scope of the Review <br /> As per the RWQCB request OEHHA reviewed the above-cited documents "to make a <br /> determination as to whether the petroleum hydrocarbons detected in soil and groundwater pose <br /> an unacceptable risk to human health or environment, or if additional sampling and analysis will <br /> be required to more fully assess risk". The documents were reviewed for scientific and <br /> regulatory issues related to the risk assessment process. The review was intended to verify the <br /> obtained results, elaborate on their analysis, and evaluate the conclusions made by the consultant. <br /> Only typographical errors reflecting the scientific integrity and the text interpretation were noted. <br /> Limitations <br /> An accurate estimate of risk from contamination at a site depends on chemical <br /> concentrations that reflected the contamination at the site. This requires samples of soil, soil-gas <br /> and water to be analyzed for toxic chemicals that are likely to be in the samples. Furthermore, <br /> the sample locations must represent the site as a whole or at least not avoid significant <br /> contamination. Finally, samples must be handled in such a way that chemical is not lost before <br /> the analysis can take place. Due to their proximity to and familiarity with sites, Regional Water <br /> Quality Control Board (RWQCB) staff can better determine the sampling locations, sample <br /> handling and needs for chemical analysis. <br /> A brief review of the "Soil Investigation and Groundwater Monitoring Report" (OEHHA <br /> was not authorized to review the site characterization) showed that only limited number of <br /> samples (seven from three locations)were analyzed for BTEX, thirty five samples from twenty <br /> nine locations were analyzed for PAHs, and eleven samples from seven locations were analyzed <br /> for selected metals. Many samples have high detection limits, others seem to have had dilution <br /> problems. <br /> According to Geomatrix, all metals' concentrations were consistent with background <br /> concentrations. No comparison with background levels, neither explanation about the basis for <br /> this conclusion were found in the provided documents. <br /> RWQCB has assumed that the soil contamination "has been adequately delineated" (p. 1, <br /> review of Soil Investigation and Groundwater Monitoring Report, dated February 25, <br /> 2004). Therefore, OEHHA has assumed RWQCB staff ensured that sampling and analysis is <br /> comprehensive and accurate for this site. <br /> Site Background <br /> The site is an approximately 7-acre, former pump station used to transport heavy crude oil <br /> by heating it (reducing its viscosity) and pumping it to San Francisco Bay Area refineries through <br />