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Thomas Berg <br /> AmMoMiIIHRA <br /> November 27,2007 <br /> Page#3 <br /> For OU1 and under residential scenario, the cumulative hazard index from <br /> exposure to contaminants in soil, soil gas, groundwater and inge tion of home grown <br /> produces was 3.0. Indoor air intrusion, ingestion of groundwater and ingestion of home <br /> grown products were the major contributors to cumulative non-cancer risk. Cumulative <br /> life time excess cancer risk for residential scenario was shown to be 8.0E-05. Major <br /> contributors were incidental ingestion of soil, indoor air intrusion lby volatile chemicals, <br /> and ingestion of groundwater (Tables F-7.2a and F-7.2b). <br /> In the case of OU2, and under similar scenario (construction worker) as OU1, <br /> cumulative hazard index was below 1.0, and cumulative life time'Icancer risk below <br /> 1.0E-06 (Tables F-7.3a and F-7.3b). Under residential scenario, umulative hazard <br /> index (soil, soil gas, groundwater, and home grown produce) was 5.0. The major <br /> contributor to this hazard index was from the ingestion of home c rown produce (HI=4). <br /> Cumulative life time excess cancer risk was determined to be 6. E-05. Major <br /> contributors to the carcinogenic risk were incidental ingestion of oil, and ingestion of <br /> groundwater (Tables F-7-4a and F-7.4b). <br /> HERD has noted that commercial industrial exposure scenario (soil, soil gas and <br /> groundwater) was only presented for OU2. Cumulative hazard index is below 1.0, and <br /> cumulative life time cancer risk is 2.0E-06. Major contributor to the cumulative cancer <br /> risk was ingestion of soil and indoor air intrusion by volatile chemicals (Tables F-7.5a <br /> and F-7.5b). Soil lead calculations, as presented using the lead pread model, are <br /> acceptable (Tables F-8.1 to F-8.1 to F-8.3 for OU2. <br /> Table F-10 contains the summary of cumulative risk levels for OU1 and OU2 for <br /> residential, construction worker and commercial/industrial receptors. <br /> Section 9.0 Risk-Based Remediation Goals: Risk based remediation goals <br /> (RBRGs) are presented in Tables 9.1for soil, 9.2 for groundwater, and 9.3 for soil gas, <br /> under the column heading "Preliminary Risk-Based Remediation Goals" under <br /> residential scenario at risk level of 1.0E-06. HERD has determined that these RBRGs <br /> are acceptable, provided confirmation sampling, after remediate n, meets the goals.of <br /> the cumulative risk management goals for residential scenario. <br /> Section 10.0 Ecological Risk Evaluation: The qualitative r sk assessment showed <br /> no major flaws, and therefore, is acceptable. <br /> Conclusion and Recommendations <br /> HERD has evaluated the human health risk assessment, ecological risk <br /> assessment and the data on the proposed risk-based remediate n goals under <br /> residential scenario, and concluded that the information and risk characterization, as <br />