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RECEIVED jUN 3 0 2014 ENVIRONMENTAL HEALTH This table provides the maximum concentration limits for soil that will not causFRHMSERVICES unacceptable human health risk to volatilization into outdoor air. No such limits have been set for soil to indoor air, but are based on actual soil vapor testing. We are proposing to side- step the vapor testing by looking at the soil sample analysis from boreholes surrounding the building. The table presents: • The concentration limits for 0 to 5 feet bgs protect from ingestion of soil, dermal contact with soil, inhalation of volatile soil emissions and inhalation of particulate emissions. • The 5 to 10 feet bgs concentration limits protect from inhalation of volatile soil emissions. Chemical Residential Commercial/Industrial Volatilization to Volatilization to (mg/kg) 0 to 5 feet bgs outdoor air 0 to 5 feet bgs outdoor air (5 to 10 feet bgs) 5 to 10 feet bgs Benzene 1.9 2.8 8.2 12 Ethylbenzene 21 32 89 134 Napthalene 9.7 9.7 45 45 PAH 0.063 NA 0.68 NA We recognize that this table has to do with volatilization into outdoor air and not to indoor air. Yet we view it as a good criterion to compare the actual soil data collected from this site in the upper 40 feet and consider it a valid metrics. We also recognize that the data used in this analysis was collected from boreholes installed in the 1990s and that a lot of remediation has occurred at this site in the interim, both natural attenuation and engineered remediation. See Table 10 for soil vapor extraction totals. Therefore, our analysis is extremely conservative. There are several boreholes/wells located around and close to the buildings at 2315 N. El Dorado Street. Soil sample analyses from these boreholes are the ones we have included at the following data points: SB-2, SB-3, SB-4, MW-1, MW-3,MW-4 &MW-5. The attached data table (Table l: Summary of Soil Boring Analytical Data) shows the following: 1. SB-2, SB-3, SB-4 — all soil samples were non-detect for the volatile compounds (BTEX) and TPH-G to a depth of 36 feet except of SB-2 sample at 36 feet which had very low concentration of BTEX (70, 9, 23, & 175 pg/kg, respectively). 2. MW-1 — soil samples were also non-detect for the volatile compounds to a depth of 31 feet; the 36 foot sample had low concentrations of 3TEX and TPH-G.