Laserfiche WebLink
Jerry Lile <br /> March 3, 2014 <br /> Page 12 of 13 <br /> CONCLUSIONS <br /> HERO reviewed the 2009 and 2012 human health screening evaluations cited above <br /> under documents reviewed. The results of these screening-level risk assessments are <br /> invalid due to major deficiencies in the 2009 HHSE and 2012 HHSE Addendum. <br /> Therefore, HERO calculated screening-level risks and presents above a synopsis of the <br /> methods, results and uncertainties. HERO's screening-level risk evaluation focused on <br /> human health and did not include Ecological Risk Assessment. <br /> Soil and groundwater data demonstrate impacts by petroleum contamination. HERO's <br /> screening level risk evaluation does not support a risk-based no further action <br /> declaration. HERO recommends risk managers either consider and accept the <br /> uncertainty in the risk estimates or reduce the uncertainty prior to making a risk <br /> management decision. The largest uncertainties center on the TPH and PAH data <br /> available. Soil risk and hazard estimates for residents calculated in HERO's screening- <br /> level risk evaluation are likely overestimated for current residents based on the age of <br /> the data presented combined with the current landscaping preventing routine contact <br /> with subsurface soil. HERO provided recommendations above to reduce the <br /> uncertainty in risk estimates, if risk managers so choose. In particular, groundwater <br /> and/or soil gas sampling for carbon fractions with speciation of aliphatic and aromatics <br /> may provide additional data to reduce uncertainty of the predicted substantial residential <br /> indoor air hazards from TPHs. <br /> Please contact meat Karen.DiBiasio(abdtsc.ca.gov or (916) 255-6633 if you have any <br /> questions. <br /> REFERENCES <br /> CalEPA, Department of Toxic Substances Control (DTSC), 2011. Final Guidance for <br /> the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air(Vapor <br /> Intrusion Guidance). October 2011. <br /> fittp://www.dtsc.ca.gov/AssessingRisk/upload/Final VIG Oct 2011.pd <br /> Code of Federal Regulations, National Oil and Hazardous Substances Pollution <br /> Contingency Plan, 40 CFR 300.430. <br /> www.ecfr.gov <br /> DTSC, 2009. Arsenic Strategies. Determination of Arsenic Remediation, Development of <br /> Arsenic Cleanup Goals. June 16, 2009. <br /> http://www.dtsc.ca.gov/Assessing Risk/upload/Arsenic-Cleanup-Goa Is-Jan09.pdf) <br /> file:20140303JL.doc <br />