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Archive for February, 2007

Analytical Considerations for Air Samples for Vapor Intrusion Investigations

Monday, February 5th, 2007

The term “vapor intrusion” refers to the migration of volatile chemicals from subsurface contaminated sources into overlying residential or commercial structures. “Historically, it was thought that vapor intrusion was only an issue where the source of the contaminants was very shallow and the magnitude of the contamination was very great. It is now known that the previous assumptions about the mechanisms that could lead to exposure to vapor intrusion were not complete (NYS DEC DER Vapor Intrusion Guidance).” For a growing number of federal, state and local agencies, as well as environmental consultants and laboratories, vapor intrusion could emerge as the next major environmental challenge.

Vapor intrusion is not a new phenomenon— for some environmental experts, it has been recognized as a potential pathway of contamination for almost 20 years. In the late 1980s, the first vapor intrusion studies were carried out to evaluate potential health effects from chronic exposure to volatile organic compounds. Presently, vapor intrusion is of growing concern to the environmental community due to a number of factors, such as increased recognition of it as a potential pathway for exposure and the risks associated with that exposure, as well as the location and the number of potential sites for investigation and remediation. With this increased focus comes ongoing debate regarding the mechanism of the exposure pathway, compliance concentrations of contaminants, identification of sites, sampling approaches, analytical methodology, use and validity of current models, screening approaches, and risk assessment, among other topics.