Phase 2 Assessments
A Phase 2 Environmental Site Assessment (ESA) is a more detailed investigation conducted after the completion of a Phase 1 ESA. While a Phase 1 ESA aims to identify potential environmental concerns and recognize recognized environmental conditions (RECs) on a property, a Phase 2 ESA involves site-specific testing and sampling to assess the extent and severity of identified environmental issues. This phase is typically triggered when the Phase 1 ESA reveals the potential presence of contamination.
Key elements of a Phase 2 Environmental Site Assessment include:
Site Sampling and Testing:
- Collection of soil, groundwater, and/or soil vapor samples to analyze for the presence of contaminants. The sampling locations are determined based on the findings of the Phase 1 ESA and any suspected areas of concern.
- Analysis of the collected samples by accredited laboratories to determine the types and concentrations of contaminants present. Common contaminants include petroleum hydrocarbons, heavy metals, volatile organic compounds (VOCs), and other hazardous substances.
- In some cases, geophysical surveys may be conducted to assess subsurface conditions and identify potential sources of contamination. This may involve the use of equipment such as ground-penetrating radar.
Data Evaluation and Interpretation:
- Evaluation of the laboratory results and other collected data to assess the extent and severity of contamination. This includes comparing the results to applicable regulatory standards and guidelines.
- Conducting a risk assessment to determine the potential impact of identified contaminants on human health and the environment. This step involves comparing the contaminant concentrations with relevant risk-based criteria.
- Assessing the feasibility of various remediation options based on the findings of the Phase 2 ESA. This includes considering factors such as the nature and extent of contamination, site conditions, and applicable regulations.
- Compilation of the findings, data, and recommendations into a comprehensive Phase 2 ESA report. This report typically includes a summary of the assessment, details of sampling and analysis, interpretations of results, and recommendations for any necessary remediation measures.
- Ensuring that the Phase 2 ESA and any recommended remediation activities comply with local, state, and federal environmental regulations. This may involve obtaining permits and approvals from regulatory authorities.
The results of a Phase 2 ESA provide valuable information for property owners, developers, and regulatory agencies to make informed decisions regarding the potential risks associated with a site and the necessary steps for remediation and redevelopment.
What is a Vapor Intrusion Assessment?
Vapor intrusion assessments are conducted to evaluate the potential for harmful vapors to migrate from contaminated soil or groundwater into indoor air spaces of buildings. This phenomenon occurs when volatile chemicals in the subsurface (such as those from petroleum products or industrial solvents) evaporate and migrate through the soil, entering buildings through cracks in foundations, basements, or utility penetrations. Once indoors, these vapors can pose health risks to occupants.
Key components of vapor intrusion assessments include:
- Conducting a thorough site investigation to identify and characterize the extent of soil or groundwater contamination. This involves soil and groundwater sampling to determine the types and concentrations of volatile organic compounds (VOCs) present.
Subslab and Indoor Air Sampling:
- Collecting air samples from beneath building slabs (subslab) and within indoor spaces to assess the concentration of vapor-forming contaminants. Subslab sampling is particularly important as it helps determine if vapors are entering the building from below.
Vapor Transport Modeling:
- Using computer models to simulate the movement of vapors in the subsurface and their potential migration into buildings. This helps in predicting the concentration of vapors that may enter indoor spaces under various conditions.
- Evaluating the potential health risks associated with exposure to vapors. This includes comparing the concentrations of contaminants in indoor air to established regulatory or health-based guidelines.
- If vapor intrusion is identified as a concern, implementing mitigation measures to reduce or prevent the entry of vapors into buildings. Common mitigation strategies include installing vapor barriers, subslab depressurization systems, and improving building ventilation.
- Ensuring that the vapor intrusion assessment and any subsequent mitigation measures comply with relevant environmental regulations and guidelines. Different regions and jurisdictions may have specific requirements for addressing vapor intrusion.
- Implementing a monitoring program to assess the effectiveness of mitigation measures over time and to ensure that indoor air quality remains within acceptable limits.
Vapor intrusion assessments are particularly important in the context of brownfield redevelopment, where contaminated sites are repurposed for new land uses. It’s essential to consider potential vapor intrusion risks to protect the health and safety of future occupants. These assessments are typically carried out by environmental consultants or experts in environmental engineering, and they often involve collaboration with regulatory agencies to ensure compliance with applicable standards.