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Jerry Lile <br /> March 3, 2014 <br /> Page 3 of 13 <br /> The scope did not include the West Side Irrigation District feature that was identified in <br /> Figure 2 of the Low Risk Closure Report(Geomatrix, 2001); if this area was used for <br /> infiltration of storm water runoff, it may have contributed to movement of groundwater and <br /> migration of potential contaminants from the pipeline. The SAIC February 12, 2009 <br /> "Human Health Screening Evaluation" neither discusses its purposes and uses, nor <br /> identifies this feature in Figure 2. Neither potential impacts of the West Side Irrigation area <br /> on contaminant migration from the pipeline to Surland Homes, nor potential contamination <br /> in the West Side Irrigation area were included in the investigations or evaluations of <br /> potential risks by either Chevron or HERO. <br /> COMMENTS <br /> 1. The results of the screening-level risk assessments by Chevron's consultants (SAIC) <br /> are invalid due to major deficiencies in the 2009 HHSE and 2012 HHSE Addendum <br /> noted below.- Therefore, as requested by DTSC Project Management Staff, HERO <br /> calculated screening-level risks and presents herein a synopsis of the methods, <br /> results and uncertainties. <br /> 2. Limitations of HHRAs Submitted <br /> A. Neither the 2009 nor the 2012 screening-level risk evaluation included <br /> • Groundwater to indoor air pathway risk evaluation <br /> • Ecological risk evaluation <br /> B. February 22, 2012 HHSE Addendum <br /> 1) Not included in the Addendum but agreed to in a 6/15/11 teleconference with <br /> SAIC were residential risks calculated using maximum concentrations from <br /> the Surland Homes neighborhood (Homes) and construction worker risks <br /> using the 95% UCL from all data including near/within the pipeline right-of- <br /> way (ROW). <br /> 2) Risks were only evaluated for ROW data. There was no risk evaluation of the <br /> Homes data, contrary to the Addendum text that states on-site (Homes) soils <br /> were evaluated in the addendum. <br /> 3) Median concentrations were used for the construction worker evaluation. <br /> 4) Outdated methods were used for calculating inhalation risks, rather than <br /> USEPA RAGS, Part F (USEPA, 2009). <br /> 5) Hazard was not calculated for some chemicals, for example cobalt and <br /> phenanthrene. <br /> 6) There was no indoor air risk evaluation. <br /> file:20140303JL.doc <br />