Laserfiche WebLink
v fir' <br /> ATC Associates Inc. <br /> (: <br /> V9%TC <br /> 1117 Lone Palm Avenue,Suite 201 <br /> Modesto,California 95351 <br /> i' 209-579-2221 <br /> fax:209-579-2225 <br /> AS SO C I ATE S INC <br /> cumulative risks for carcinogens, and the incremental hazard quotients and cumulative hazard <br /> index for non-carcinogens based on the highest reported concentration of each constituent <br /> detected in the vapor samples are provided in the following table. <br /> Analyte Incremental Risk Hazard Quotient(Non- <br /> (Carcinogens) carcinogens) <br /> Freon 12 -- 3.8E-05 <br /> Acetone -- 2.1 E-03 <br /> Methylene Chloride 1.1E-09 6.5E-06 <br /> �. Carbon disulfide -- 6.5E-05 <br /> MTBE 5.2E-10 1.5E-06 <br /> Benzene 5.2E-07 1.4E-03 <br /> 60 Toluene -- 4.6E-04 <br /> Tetrachloroethene 3.2E-08 3.6E-04 <br /> Eth (benzene -- 2.1 E-05 <br /> lo. m, -X lene -- 1.3E-03 <br /> o-X lene -- 2.0E-04 <br /> 4-Eth (toluene -- -- <br /> 1,3,5- 6.1E-04 <br /> Trimeth lbenzene <br /> 1,2,4- 1.7E-03 <br /> Trimeth lbenzene <br /> #60 Cumulative 5.5E-07 8.3E-03 <br /> 6# Based on the available soil vapor data and modeling the highest analyte concentrations <br /> detected, the incremental hazard quotient values and cumulative hazard index value did not <br /> exceed the threshold of 1.0 for non-carcinogens. The incremental and cumulative risk values <br /> did not exceed the protection value for carcinogens of 1.0E-06 for residential land use and 1.0E- <br /> �' 05 for commercial/industrial land use. Copies of the modeling spread sheets are provided in <br /> Appendix D. <br /> CONCLUSIONS <br /> Soil vapor sampling activities were completed in general accordance with ATC's Soil Gas <br /> Survey Workplan, Diesel Performance Inc., dated December 2, 2010. Analytical results <br /> associated with the soil vapor samples collected from SG-1, SG-2, SG-3, and SG-4 indicate that <br /> some of the analytes of interest were present at low concentrations that did not exceed the <br /> +� established ESLs and CHHSLs for commercial/industrial land use. The concentrations of <br /> benzene detected in all four of the soil vapor samples exceeded the residential CHHSL for this <br /> ' constituent. <br /> 6W <br /> As a conservative approach, a Tier 2 Evaluation was performed. This evaluation consisted of <br /> computerized modeling that focused on evaluating site conditions using site specific parameters <br /> and generic Johnson and Ettinger default modeling parameters, in an attempt to determine <br /> whether the site poses a current or future health risk based on available site data. The <br /> S:1Environmenta1\62577\Reports\2011 Soil Gas.doc 7 ATC Associates Inc. <br /> V <br /> V <br />