Tech Focus: Soil Vapor Sampling
Soil vapor sampling is a key component of environmental investigations because of its ability to identify potential environmental hazards that could impact human health and the feasibility of land development. The process plays an essential role in the assessment and management of contaminated sites by collecting and analyzing soil gas to detect volatile organic compounds and other contaminants (e.g., methane, hydrogen sulfide, naphthalene, mercury) present in the subsurface.
When hazardous materials (e.g., industrial solvents) or petroleum products (e.g., gasoline or fuel oils) are present in soil or groundwater, the volatile fractions of these contaminants can migrate through the soil pores, potentially entering buildings and affecting indoor air quality for occupants. Methane gas—often present in or near municipal solid waste landfills, areas of reclaimed land with buried organic matter (wetlands), or petroleum or natural gas reservoirs/seeps—is highly flammable and can accumulate in or around buildings, leading to the formation of potentially explosive mixtures with air. Additionally, unchecked methane hazards pose significant safety risks and can lead to structural damage.
By evaluating potential sources and collecting soil vapor samples, environmental professionals can detect contaminants early on, assess the extent of contamination, and develop appropriate strategies to alleviate project risks. Applicable technologies include active sub-slab depressurization (with or without vapor barriers), air sparging/soil vapor extraction, bioventing, and active or passive venting systems. For project teams, understanding subsurface vapor conditions allows them to comply with environmental regulations, proactively design appropriate remediation strategies (thereby avoiding costly delays or redesigns), and ultimately mitigate risks to human health and the environment.
Overall, the practice of soil vapor sampling greatly enhances the overall sustainability and safety of land development projects. By identifying and addressing potential hazards at the beginning of a project, developers can avoid long-term liabilities and create safer sites and healthier communities. This practice supports the broader goal of environmental protection by making sure that land use changes do not exacerbate known environmental issues or create new ones.
Gregory C. Wyka is a licensed professional geologist with over 16 years of diversified experience in environmental consulting and regulatory government. Well-versed in many land development services and practice areas, Wyka’s primary project experience includes large-scale, multi-parcel waterfront redevelopment projects enrolled in the New York State Brownfield Cleanup Program and/or the New York City Voluntary Cleanup Program. His expertise includes brownfield redevelopment and its core phases—due diligence, site investigation, conceptual site modeling, and remediation, including in-situ solidification/stabilization. Wyka is currently serving as President of the New York State Council of Professional Geologists.