Text Box: Text Box: Page # Text Box: Volume 10, issue 2 Text Box: and the integrity of any confining units or other barriers to migration of groundwater. Groundwater movement and its associated impact upon distance from the source to the receptor should be considered. Three factors that affect contaminant levels in groundwater that affects contaminant levels in soil gas are dispersion, dilution, and recharge”. On page 42… “… because vapor intrusion investigations often require sampling near, in, or under the places where people live or work, building trust and cooperation is a critical path item for a successful project. To maximize chances of getting permission to sample in areas where existing data suggest that it should be done, it is necessary to target the outreach. This is usually a difficult, time-consuming process, but it can be made easier by a successful community-wide program of education,…” On Page 43… “...building triage approach involves assessing the magnitude of the subsurface concentrations (e.g., soil gas, groundwater) into zones to assist in targeting initial investigations. The zones are primary, secondary, tertiary”. On Pages 43—44... ‘For a large site involving a significant number of buildings, identify primary, secondary, and tertiary buildings based on the magnitude of groundwater and/or soil gas concentrations. Then, Text Box: as necessary, implement an interior investigation (e.g., subslab soil gas sampling, indoor air sampling) initially in the primary buildings. Some states may start with an interior sampling effort, targeting a primary, secondary, and tertiary zone, based solely on groundwater concentrations. If some of the primary buildings reveal evidence of unacceptable vapor intrusion, the interior investigation is expanded to the secondary buildings. This approach is referred to as a “step-out process,” where buildings adjacent to impacted buildings are investigated in an outward, sequential manner until a perimeter with no impacts (or below screening levels) is established’. For more information go to : http://www.itrcweb.org/gd.asp Text Box:

ITRC Vapor intrusion intro - continued

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