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BALE®BVFLDER Bright People.Right Solutio— DISCUSSION OF FINDINGS CONCLUSIONS AND RECOMMENDATIONS The following conclusions and recommendations are based upon analytical results and Kleinfelder's findings. The soil analytical results were compared (as applicable) to three published regulatory screening levels (SLs) including California Human Health Screening Levels (CHHSLs), Environmental Screening Levels (ESLs) and Regional Screening Levels (RSLs). The CHHSLs were developed by the Office of Environmental Health Hazard Assessment (OEHHA) on behalf of the California Environmental Protection Agency (Cal/EPA) in a document dated November 2004 and revised January 2005. ESLs were developed by the California Regional Water Quality Control Board, San Francisco Bay Region, dated May 2013. RSLs, formerly known as PRGs, were developed using risk assessment guidance from the EPA Superfund program with reference tables dated May 2013. These various screening levels (SLs) are similar in that they were developed to assist in evaluating sites impacted by releases of hazardous chemicals. The various screening levels are risk assessment tools which include conservative values for commonly detected contaminants, but are not regulatory limits or cleanup standards, although regulatory agencies may and have chosen some of these values as such. Some of these screening levels, such as the ESLs also take into consideration leaching potential to groundwater. The presence of a chemical at concentrations in excess of a screening level does not necessarily indicate that adverse impacts to human health or the environment are occurring; but does indicate that additional evaluation may be warranted. Kleinfelder compared analytical results for soil samples collected in the UST excavation and from stockpiled soil (Tables 2 and 3) to SLs associated with commercial/industrial land use given that the soil is within the French Camp Road right of way and is anticipated to be re-used on the larger roadway project and not for residential land use. Results from Table 1 were not compared to SLs as this soil and the UST have been disposed of offsite under hazardous waste manifest and the concentrations in Table 1 are from soil within the tank and are not representative to remaining onsite soil. The following table is a summary of concentration ranges for the two analytes detected from the requested analyses with comparison to,the noted SLs: 125819.E01/ST013RO732 Page 6 of 10 December 11, 2013 Copyright 2013 Kleinfelder