Vapor Intrusion

Vapor Intrusion

Peak Environmental, A Nova Group GBC Company and our Licensed Site Remediation Professionals (LSRPs) have extensive experience investigating and remediating soil-gas and vapor intrusion conditions at a wide variety of sites ranging from residential properties to large industrial facilities. The New Jersey Department of Environmental Protection (NJDEP) has published a Vapor Intrusion Technical Guidance (VITG) document, which includes vapor intrusion screening levels (VISL) for evaluating the need to perform vapor intrusion (VI) sampling, monitoring and mitigation. Peak has the expertise and equipment to evaluate the area where groundwater impact is above the NJDEP Ground Water Screening Levels (GWSL), complete and submit the NJDEP required documents, collect the appropriate samples, evaluate data, and develop any necessary monitoring programs or mitigation actions. Peak plans all projects with the primary goal of closure through protection of potential receptors, and ensures all included steps support advancement toward that goal.

When concentrations of volatile organic compounds (VOC) in groundwater exceed a NJDEP GWSL within a threshold distance of a receptor, Peak’s experienced professionals typically start a VI project by developing a preliminary conceptual site model (CSM) as a basis for locating sub-slab soil-gas samples. Based on the results of the sub-slab soil-gas sampling, indoor air samples may be required. Combined interpretation of the sub-slab and indoor air sample results subsequently yields a decision toward either additional monitoring (sampling), mitigation of the source and vapors, or no further action. The NJDEP provides a classification system for buildings that contain concentrations of compounds in indoor air that exceed NJDEP Indoor Air Screening Levels (IASL) and Rapid Action Levels (RAL). The NJDEP designates buildings that contain concentrations greater than IASL as a Vapor Concern (VC), and buildings that contain concentrations greater than RAL as an Immediate Environmental Concern (IEC). The VC and IEC classifications must be managed as prescribed in relevant sections of NJAC 7:26E, the VITG and the NJDEP Immediate Environmental Concern Technical Guidance document. If the building is classified as a VC or IEC, mitigation is required and regulatory timeframes in the process apply.

Peak has a CIH on staff, and utilizes sample data and building information to determine whether contaminants in air are related to the groundwater plume or to background sources. Peak has helped our clients perform investigation, mitigation and monitoring, including submitting the required paperwork, reports and forms, under both VC and IEC conditions to meet the regulatory timeframes and achieve regulatory compliance for vapor intrusion issues.

When needed, Peak has performed interim remedial measures (IRM) to reduce contaminant concentrations in indoor air, and then designed and installed sub-slab depressurization systems (SSDS) at residential, commercial and industrial buildings. Peak retains certified installers to design and install the systems. Peak will also determine whether an institutional control such as a deed notice may be required and can implement such controls as needed. Following the installation of a SSD system, Peak maintains and monitors the system to ensure it operates as designed, remains effective, and is utilized for only as long as necessary to achieve project closure. Peak and our LSRPs will prepare all required paperwork, forms and technical reports in accordance with applicable regulation.

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