Construction of brownfields and water contamination

Above, an abandoned foundry.

By Ryan Moore and Ryan Miller

New construction in old vacant industrial properties, known as brownfields, has increased dramatically over the past decade. Even before the COVID-19 pandemic, the growth of e-commerce was driving a revolution in new construction of industrial warehouses and last mile distribution centers, which has only accelerated since early 2020. According to a source, the United States will need a billion square feet of industrial warehouse space over the next five years to meet e-commerce demand.1 Mixed-use residential / commercial redevelopment of brownfields also continues steadily in many parts of the United States.

Due to the continued need for affordable land in areas accessible to highly populated areas and fueled by tax incentives, many of these future buildings will be built on or near brownfields where chemical releases have occurred. Chemical vapors are formed when chemicals containing chlorinated solvents, petroleum hydrocarbons or other volatile compounds, commonly used in industry, are spilled or inappropriately disposed of. Over time, these chemicals often migrate through soil, contaminated groundwater and form plumes of chemical vapors.

Building occupants could be exposed to indoor air containing these vapors if a building is constructed within a vapor plume imprint of contaminants. Inhalation of chemical vapors is often hazardous to human health, even at concentrations in indoor air not detected by odor (i.e. below the odor threshold).

Additionally, in the past five years alone, there has been increased awareness of a class of chemicals known as per- and polyfluoroalkyl substances (PFAS) and their widespread impact on public drinking water supplies. and private. According to the Environmental Working Group, more than 200 million people could drink water contaminated with these “forever” chemicals that do not degrade, leading to accumulations of PFAS in nearly all of America’s blood systems.2 For these reasons, some PFAS species are in the process of being designated as dangerous substances by the Environmental Protection Agency. Many states have regulations in place, or under development, dealing with several PFAS compounds as such.

Some of the highest PFAS exposure threats that may require active mitigation in the future may be found in or downstream of old or current military bases, airports, landfills, petrochemical facilities, pulp mills, and papers, metal plating facilities, textile and plastics manufacturers, to name a few. In many of these facilities, areas affected by PFAS are often associated with shallow groundwater near the locations of outflow sources or sewer collection ponds where training or fire testing has been carried out. using aqueous film-forming foams (AFFF) containing PFAS.

Once in groundwater, it is random if the PFAS contaminants pose a risk to the environment or human health, depending on factors such as the species and concentration of PFAS, the speed of groundwater movement. and the distance to the drinking water well or other receptors.

[Editor’s Note: The recently passed Infrastructure Bill includes a $10 billion provision to clean up PFAS.]

Proactive measures to mitigate the risk of environmental liability

Understand your site history

It starts with due diligence. It is essential that owners and developers understand the history of the property. This understanding typically involves a Phase I environmental site assessment (ESA), which includes information gathering and interviews to understand what chemicals have been stored, where they have been stored, and how they have been used. With respect to PFAS, it is critical to know whether any testing of fire training or fire prevention systems has ever taken place on the property and whether manufacturing operations included the use of potentially harmful chemicals.

In addition, current and future regulations that could affect the facility should be understood. Research guidelines regarding the use of groundwater in the vicinity of your facility and whether potential receptors (i.e., a potable well or watercourse) are located near a facility. It is advisable to retain the services of a legal advisor specializing in PFAS before undertaking any underground investigation activity to assess the contamination by PFAS or before a real estate transaction requiring an environmental assessment of the site (phase 1 or phase II EES).

Safe, economical and efficient means to manage the risk of vapor intrusion

Years ago, industry leaders in vapor mitigation assessed trends and predicted the need for a contaminating vapor barrier to address the increased risk of vapor intrusion resulting from construction on highways. brownfields and other properties degraded by the environment. Advanced vapor intrusion mitigation systems incorporate the latest technological innovations to provide the highest chemical protection available. These advanced systems include patented, state-of-the-art materials including metallized films and advanced nitrile asphalt latex (developed by Land Science®) that provide up to a hundred times more chemical protection than traditional systems from mitigation of vapor intrusions.

While providing the highest level of vapor intrusion protection, these advanced systems are often easier and faster to install than older systems and are competitively priced. Real estate developers and brownfield contractors are rapidly increasing the integration of these systems into their construction plans to deal with any potential risk of steam intrusion, known or unknown, and to ensure that the construction project meets schedule and reduce any potential future liability. Additionally, comparative cost analyzes have shown that it is often less expensive to preemptively mitigate vapor intrusion than to investigate and mitigate once the problem is detected.

If the impacts of PFAS on groundwater are confirmed, act quickly

While an investigation resulting from the due diligence activities described above has detected PFAS contamination in groundwater at concentrations requiring remediation, an approach has demonstrated long-term effectiveness and economy in removing PFAS and other organic contaminants in groundwater. This corrective approach involves a in situ PFAS treatment method using a colloidal form of activated carbon applied directly to or upstream of a contaminated area in groundwater. In this process, materials from the aquifer are transformed into filter media, cleaning the impacted groundwater as it migrates through the treatment area. As the treatment is driven by the natural movement of groundwater and does not require mechanical pumping, it is also very economical.

Colloidal Activated Carbon (CAC), a proprietary and patented technology commercially available as PlumeStop® via REGENESIS®, rapidly removes PFAS constituents from groundwater and immediately contains them. Treatment therefore eliminates the risk by removing the potential exposure to these chemicals by a downstream receptor. These CAC applications have been applied to many PFAS contaminated groundwater sites and are designed to stop the continued transport of PFAS in groundwater for decades. In addition, performance guarantee options for CAC treatment are available from the manufacturer.

As brownfield redevelopment continues to increase, so does the occurrence of previously unknown environmental contamination. Understanding the potential environmental liability risks and the methods to mitigate those risks is key to ensuring a safe environment for future building occupants and avoiding unnecessary and potentially very costly environmental exposure.

The references

1. Latest trends in industrial real estate Here to stay – Development of the area. Accessed October 5, 2021.

2. Andrews DQ, Naidenko OV. Population-wide exposure to per- and polyfluoroalkylated substances from drinking water in the United States. About Sci Technol Lett. 2020; 7 (12): 931-936. doi: 10.1021 / acs.estlett.0c00713

Ryan moore – As the REGENESIS PFAS manager, Moore focuses on working with environmental professionals and industry to communicate effective and proven approaches to manage sites where PFAS contaminants exceed regulatory standards. He has over 20 years of experience in in situ remediation, environmental project management and laboratory account management for multimedia contamination sites across the United States.

Ryan miller – As responsible for the Eastern region of Earth Science® of REGENESIS, Inc., Miller’s role includes providing technical support in the design and installation of TerraShield, Nitra-Seal, MonoShield and Retro-Coat vapor mitigation systems, and educating the environmental community on vapor intrusion barrier technology advancements, implementation, and quality control. He has extensive experience in the environmental consulting industry, focusing his career on brownfield redevelopment projects and specializing in vapor intrusion mitigation.

About Meredith Campagna

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