SITE INFORMATION AND CORRESPONDENCE (3)

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(c) Scenario 3: Dissolved Phase Benzene Concentrations Only in Groundwater (Low concentration groundwater scenarios with or without 02 measurements): i. For bioattenuation zone without oxygen measurements or oxygen <4% and benzene concentration are <100 pg/L, the bioattenuation zone: • Shall be a continuous zone that provides a separation of at least 5 feet vertically between the dissolved phase benzene and the foundation of existing or potential building; and • Contain total TPH (TPH-g and TPH-d combined).<100 mg/kg throughout the entire depth of the bioattenuation zone. Yes ❑ No ❑ NA ii. For bioattenuation zone without oxygen measurements or oxygen <4% and benzene concentration are >100 pg/L but <1000 pg/L, the bioattenuation zone: • Shall be a continuous zone that provides a separation of at least 10 feet vertically between the dissolved phase benzene and the foundation of existing or potential building, and • Contain total TPH (TPH-g and TPH-d combined) <100 mg/kg throughout the entire depth of the bioattenuation zone. ❑ Yes ❑ No ❑ NA iii. For bioattenuation zone with oxygen 24% and benzene concentration <1000 pg/L, the bioattenuation zone: • Shall be a continuous zone that provides a separation of at least 5 feet vertically between the dissolved phase benzene and the foundation of existing or potential building, and • Contain total TPH (TPH-g and TPH-d combined) <1 0 0 mg/kg throughouthout the entire depth of the bioattenuation zone. ❑ Yes ❑ No ❑ NA (d) Scenario 4: Direct Measurement of Soil Gas Concentrations ❑Yes ❑ No ❑ NA i. Soil Gas Sampling Locations — No Bioattenuation Zone: • Beneath or adjacent to an existing building: The soil gas sample shall be collected at least 5 feet below the bottom of the building foundation) • Future construction: The soil gas sample shall be collected from at least 5 feet below the ground surface (bgs) ❑ Yes ❑ No ❑ NA i