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Jerry Lile <br /> March 3, 2014 <br /> Page 4 of 13 <br /> C. 2009 HHSE <br /> 1) Soil Exposure point concentrations were calculated using ProUCL 4.0 and <br /> averaging the soil data. The density of soil sampling was less than one <br /> sample per residential lot and therefore is not sufficient for averaging the <br /> data. The soil data were collected from several locations within the Surland <br /> Homes development and several locations in the right of way along W. Byron <br /> Road. The 2009 HHSE did not discuss that some of the data were collected <br /> from outside the Surland Homes development in the ROW. <br /> 2) Groundwater risks were not evaluated for all chemicals of concern (COCs). <br /> For example, the 2009 HHSE Appendix B.1, Table 2, "Historical <br /> Groundwater Analytical Data" does not contain all the footnotes or <br /> naphthalene and phenanthrene data presented in Table A-2 of the 1999 <br /> Geomatrix investigation report. Previously HERO commented in our <br /> December 10, 2003 memorandum that naphthalene and phenanthrene were <br /> detected in water in GB-1 over 10-fold higher than the method blank, thus <br /> they are both considered site-related contaminants. Accordingly, <br /> naphthalene (4.8 4g11) and phenanthrene (2.5 4g/1) results need to be <br /> included in, and carried through, the quantitative human health screening <br /> evaluation. <br /> 3) Outdoor air inhalation exposures by residents and construction workers to <br /> volatile chemicals were miscalculated. Risks were estimated from bulk soil <br /> concentrations emissions (in Tables 22 and 23) with miscalculations of <br /> emissions and risks as evidenced by toluene and ethylbenzene values <br /> interchanged for Diffusivity in air (Di), Henry's constant (Hc), and organic <br /> carbon-water partition coefficient (Koc). <br /> 4) Indoor air risks were not evaluated. The VOC data collected suggest the <br /> need to quantitatively evaluate risks from indoor air exposures. To date there <br /> have been no soil gas investigations_ HERO is most concerned about <br /> potential indoor air inhalation exposures from the carcinogens ethylbenzene <br /> and naphthalene detected in historical soil and groundwater. <br /> 5) Exposures due to inhalation of particulates for residents were applied to <br /> construction workers, thus underestimating construction workers' potential <br /> exposures, risks, and hazards. <br /> 6) The HHSE did not employ recent guidance available utilizing scientific <br /> advances in assessment of exposure and risk(DTSC, 2004; US EPA, 2004). <br /> file:20140303)L.doo <br />