SITE INFORMATION AND CORRESPONDENCE (3)

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ii. Soil Gas Sampling Locations —with Bioattenuation Zone: The criteria in Column A in the table below apply if the following requirements for a bioattenuation zone are satisfied: • Minimum of-5feet of soil between the soil vapor measurement and the foundation of an existing or ground surface of future construction. .0 TPH (TPHg + TPHd)-is <100 ppm (measured in-at least two depths within the 5-ft zone) Oxygen is >4% measured at the bottom of the 5-ft zone: ❑ Yes ❑ No ❑ NA Soil Gas Criteria (gag1m ) a A- With Bioattenuation Zone B- No Bioattenuation Zone , F Residential Commercial Residential' Commercial Constituent Soil Gas Concentration (pg/rn SolI Cas Concentration lm Benzene <85,000` <280 000 <85 <280. . Eth Iberizene <1,1001000 <3,600,000 <1,100 - <3,600 Naphthalene <93,000 <310,00 <93 <310 Notes: A 1000-fold bioattenuation of petroleum vapors is assumed for the bioattenuation zone. 2. Is a site-specific risk assessment for the.vapor intrusion pathway conduct and does-the assessment demonstrate that human health is protected for the satisfaction of the regulatory agency? { ❑ Yes ❑ No ❑ NA 3. Does the regulatory agency determine that petroleum vapors migrating from soil or groundwater will have no significant risk of adversely affecting human health as a result of controlling exposure through the use of mitigation measures or through the use of institutional or engineering controls? I 'l ❑ Yes ❑ No ❑ NA { C. Direct Contact and Outdoor Air Exposure: The site is considered low-threat for direct contact and outdoor air exposure if it meets any of the following: l 1. Are maximum concentrations of petroleum constituents in soil less than or equal to those listed i in the following table for the specifieddepth below ground surface? El Yes ❑ No ❑ NA I