By: Charles Leachman, P.G. – LFI Senior Geologist
Vapor Intrusion is the pathway from a subsurface contaminant source into overlying buildings. The predominant compounds of concern are volatile organic compounds with benzene, PCE, and TCE comprising nearly 95% of all vapor intrusion issues.
Impacted soil and groundwater have been regulated for many years, but currently less than half of our 50 states have any published regulations or regulatory guidance regarding vapor intrusion. The US EPA only has Draft Guidance on the topic. Impacted soil may be particularly detrimental to construction workers and small children exposed to the specific areas where impacted soils exist. Impacted groundwater is a significant concern to humans who may utilize this as a source for drinking water. Impacted vapors have the potential to negatively affect all things exposed.
With respect to groundwater issues, the source area of the problem can usually readily be identified, and there are generally numerous options available to remediate the impact, including the use of an alternate supply source. Vapor intrusion tends to be more difficult to assess, as multiple potential sources within the home (stored chemicals, cleaners, HVAC emissions, etc.) complicate the investigation process. Vapor intrusion remediation can be as easy as installing a fan to as complicated as laying down an extensive engineered barrier system. Vapor intrusion investigations are typically performed in office buildings or residences, which makes ramifications much more personal to further complicate matters.
Vapor intrusion investigation is often the first item left off the list when dealing with soil/groundwater plume contamination scenarios. Lack of knowledge regarding indoor air quality issues and cost considerations tend to contribute to the omission of an indoor air/vapor intrusion evaluation.
LFI is a leader in vapor intrusion and vapor intrusion investigation/mitigation. Our experience includes extensive assessment work for the Kentucky Department for Environmental Protection to evaluate petroleum-based soil vapor intrusion source areas in a fractured bedrock setting; evaluation of private-sector client issues related to vapor emissions originating from groundwater affected by chlorinated solvents; and the assessment of potential vapor intrusion impacts to indoor air in a concession stand at a city park located near a former dump site. LFI staff has undergone advanced soil vapor intrusion training at strategic workshops in Seattle, Los Angeles, and Norfolk. We have helped educate our peers and the public through vapor intrusion presentations to the Kentucky Chamber of Commerce and the Kentuckiana Chapter of Hazardous Material Managers.
While the degree of risk may be debatable, vapor intrusion is now on the radar of regulators and is here to stay.
Contact Charles Leachman at cleachman@lfienvironmental.com or (502) 721-5714 for more information or further guidance on these issues.