Describe What Brownfields Are And How They Can Be Assessed.

Understanding and Assessing Brownfields: A Comprehensive Guide

Brownfields, often overlooked patches of urban landscape, represent a significant challenge and opportunity for sustainable development. These are underutilized or abandoned properties where past industrial or commercial activities have left behind environmental contamination. Understanding what constitutes a brownfield site and how to properly assess its environmental condition is crucial for successful remediation and redevelopment. This comprehensive guide delves into the intricacies of brownfields, exploring their characteristics, assessment methodologies, and the path toward revitalization.

What are Brownfields?

Brownfields are sites that may be contaminated but are not necessarily hazardous waste sites under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). They are often characterized by real or perceived environmental contamination that complicates their reuse and redevelopment. This contamination can stem from various sources:

Common Sources of Brownfield Contamination:

• Manufacturing Plants: Former factories, mills, and processing plants often leave behind residues of heavy metals, solvents, petroleum products, and other hazardous substances.
• Gas Stations: Underground storage tanks (USTs) at gas stations frequently leak petroleum products into the surrounding soil and groundwater.
• Dry Cleaners: The use of perchloroethylene (PCE) and other solvents in dry cleaning operations results in widespread soil and groundwater contamination.
• Landfills: Improperly managed landfills can leach contaminants into the surrounding environment, impacting soil and water quality.
• Railroads and Transportation Hubs: These areas often have a history of spills, leaks, and the accumulation of various hazardous materials.
• Military Installations: Former military bases can have significant contamination from munitions, fuels, and other hazardous materials.

The presence of contamination doesn't automatically label a site as a brownfield. The key distinguishing factor is the potential for reuse and redevelopment. Unlike Superfund sites (designated under CERCLA), brownfields are often suitable for redevelopment with appropriate investigation and remediation.

The Importance of Brownfield Assessment

Before any redevelopment can occur, a thorough assessment of the brownfield site is essential. This process involves identifying and characterizing the extent and nature of contamination, evaluating potential risks to human health and the environment, and determining the necessary remediation strategies. The assessment plays a critical role in:

• Protecting Human Health and the Environment: A proper assessment prevents exposure to hazardous substances, protecting the health of workers, residents, and the surrounding ecosystem.
• Facilitating Redevelopment: By understanding the extent of contamination, developers can plan and budget for effective remediation, enabling the site's reuse.
• Reducing Liability: A comprehensive assessment can help reduce liability for future environmental issues associated with the site.
• Guiding Remediation Decisions: The assessment data informs the selection of appropriate and cost-effective remediation technologies.
• Attracting Investment: A well-documented assessment demonstrating a clear path to remediation can attract investors interested in brownfield redevelopment projects.

Phases of Brownfield Assessment

A typical brownfield assessment involves several phases, each with specific objectives and methodologies:

Phase I Environmental Site Assessment (ESA):

This is a preliminary investigation that focuses on gathering historical information about the property. It involves reviewing historical records, conducting interviews with previous owners and occupants, and conducting a visual site inspection. The goal is to identify potential sources of contamination and assess the probability of contamination based on historical use and surrounding properties. Phase I ESAs often follow a standardized ASTM E1527-13 or similar protocol.

Phase II Environmental Site Assessment:

If the Phase I ESA identifies potential contamination, a Phase II ESA is conducted. This involves collecting environmental samples (soil, groundwater, surface water, air) and analyzing them for the presence of contaminants. The location and extent of contamination are determined through sampling and analysis. This phase helps delineate the area impacted by contamination. Specific analytical methods are tailored based on the potential contaminants identified in the Phase I ESA.

Phase III Environmental Site Assessment:

Phase III is the remediation phase, where contaminated materials are removed or treated in place. This stage requires a detailed remediation plan based on the findings of Phase II. The chosen remediation technique depends on the type and extent of contamination, the nature of the site, and regulatory requirements.

Methods Used in Brownfield Assessment

Various methods are employed throughout the assessment process. These include:

• Historical Records Review: Examination of deeds, maps, aerial photographs, industrial records, and other historical documents to determine past land uses and potential contamination sources.
• Site Reconnaissance: A visual inspection of the property to identify potential sources of contamination, signs of past activities (e.g., buried drums, stained soil), and potential environmental receptors (e.g., nearby water bodies, residential areas).
• Soil Sampling: Collection of soil samples at various depths and locations to analyze for the presence of contaminants. Sampling strategies are designed to accurately represent the extent of contamination.
• Groundwater Sampling: Collection of groundwater samples from monitoring wells to determine the extent of groundwater contamination and its direction of flow.
• Surface Water Sampling: Collection of surface water samples from nearby streams, rivers, or lakes to assess the potential for surface water contamination.
• Air Sampling: Collection of air samples to assess the presence of volatile organic compounds (VOCs) in the air.
• Geophysical Surveys: Non-invasive methods like ground-penetrating radar (GPR) and electromagnetic induction (EMI) can help identify subsurface anomalies and potential contamination sources without extensive excavation.
• Laboratory Analysis: Environmental samples are sent to accredited laboratories for analysis to identify and quantify the contaminants present.

Data Interpretation and Reporting

The results of the assessment are summarized in a comprehensive report that includes:

• Site History and Description: Detailed information about the property's past uses, potential contamination sources, and surrounding environmental features.
• Methodology: Description of the sampling and analytical methods used.
• Data Analysis: Presentation of the analytical results, including contaminant concentrations, spatial extent of contamination, and potential environmental pathways.
• Risk Assessment: Evaluation of the potential risks to human health and the environment posed by the identified contamination.
• Remediation Recommendations: Suggestions for appropriate remediation technologies based on the assessment findings, regulatory requirements, and site-specific conditions.

Regulatory Considerations

Brownfield assessments must comply with federal, state, and local regulations. These regulations vary depending on the location of the site and the type of contaminants involved. Key regulatory agencies involved in brownfield redevelopment often include the Environmental Protection Agency (EPA), state environmental agencies, and local health departments. Understanding these regulations is critical for successful brownfield redevelopment.

Conclusion

Brownfield assessment is a critical process that ensures responsible and sustainable redevelopment of contaminated properties. By carefully investigating the environmental conditions of a brownfield site, developers can mitigate risks, ensure compliance with environmental regulations, and pave the way for successful revitalization projects. This comprehensive approach, encompassing historical review, field investigation, laboratory analysis, risk assessment, and remediation planning, is vital for transforming these often-overlooked areas into valuable community assets, contributing significantly to sustainable urban development and environmental protection. The investment in thorough assessment translates directly to the long-term success of the project and safeguards the environment and public health.