Microplastics, Emerging Contaminants, and the Construction Industry

Judd Mahan is a distinguished Project Director at Tetra Tech, a renowned environmental consulting firm. With a deep passion for environmental science and a commitment to sustainable progress, Judd has established himself as a leader in the field. Over the course of his career, he has spearheaded numerous environmental assessments, remediation efforts, and restoration projects, showcasing his expertise in balancing technological advancements with the preservation of natural ecosystems.

Judd's journey has been marked by his unwavering dedication to fostering positive relationships. He has fostered strong connections with colleagues, clients, and regulatory agencies, a testament to his collaborative spirit and exceptional communication skills. With a solid foundation in earth and environmental science concepts, he has consistently delivered successful outcomes across various domains.

Plastics, or synthetic polymers, often provide low cost, durable, and versatile products. However, questions are increasingly raised about the use and disposal of plastics and the potential for negative human health and environmental consequences. In recent years, concern over microplastics, particles less than 5 millimeters in size, has emerged as studies demonstrate widespread occurrence of the particles in soil and surface water, as well as in the bodily tissues of wildlife and humans. For example, a study published by the American Chemical Society in 2021 indicated that adults consume approximately 883 microplastic particles per day while children consume approximately 553 particles per day. Studies are ongoing to determine the effects of microplastics in the environment and in humans.As a geologist andenvironmental consultant, I workacross sectorsincludingconstruction, manufacturing, and energy. I am monitoring the status of microplastics as an emerging contaminant because the developments could have profound impacts.

What are emerging contaminants? They are substances that are not currently regulated, and for which there is limited knowledge of the toxicity and effects on humans and the environment.  I have been working in private industry as an environmental consultant for over twenty years. Other emerging contaminants are already affecting how we do business. An example that many folks have probably heard of are per- and polyfluoroalkyl substances (PFAS), also widely referred to as “forever chemicals”.The U.S. Environmental Protection Agency (EPA) is in the process of establishing drinking water standards for PFAS. Establishment of drinking water standards for a substance tends to have a domino effect and triggers other actions such as standards for water in lakes and streams, as well as state and local regulations which can be more restrictive than federal limits. Other effects include the phasing out of those substances in consumer products. It is early in the process, but microplastics have joined the group of emerging contaminants. What does that mean generally, and what could it mean for the construction industry?

The Interstate Technology and Regulatory Council (ITRC) published a microplastics guidance document for state environmental regulatory agencies in February 2023. The ITRC definition of microplastics includes particles that “consist of solid polymeric materials to which chemical additives or other substances may have been added.” 

Plastics commonly used in construction include acrylic, polycarbonate, polypropylene, polystyrene, and polyvinyl chloride.  Polystyrene, in the form of restaurant takeout containers, is one of the most common single use plastics. Expanded polystyrene (EPS) is also a valuable building material due to desirable thermal insulating properties. Insulating foam panels used for building walls and floors are made of EPS. However, research published in the March 2023 issue of the journal Environmental Science and Technology demonstrated that 50% or more of plastic foam particles found in tributaries, beaches, and surface water of Lake Ontario was sourced from construction activities. The presence of bromine from flame retardants in building materials allowed the researchers to determine the portion of microplastics originating from construction activities. Foam packaging for food and other consumer products does not normally incorporate bromine.

Much of my early career was spent installing groundwater monitoring wells and collecting soil and water samples at sites such as petroleum distribution facilities, manufacturing plants, and landfills. My current work involves environmental permitting for new infrastructure—new port facilities in South Carolina and Georgia, highway projects in North Carolina, and alternative energy projects across the U.S. The South Carolina port facilities work is taking place on a large brownfields site. Brownfields are properties that were previously used for industrial purposes and have a history of contamination. I am working closely with the construction contractor and one of the challenges that has come up is how to manage PFAS which might be present in soil or groundwater. During site prep, excess soil will be generated and require disposal. Utility excavations will require dewatering and disposal of the liquids. South Carolina has no regulations regarding PFAS and the federal regulations are still a work in process. That leaves a lot of gray area for those trying to get work done—an emerging contaminant dilemma. Stakeholders are concerned about PFAS and therefore it must be addressed. Emerging contaminants can affect our work even before there are regulations in place.

In the United States, there is little in the way of regulations regarding microplastics. Many jurisdictions are in an information-gathering mode.For instance, at the state level in California, the State Water Resources Control Board (SWRCB) will begin a 2-year program to test drinking water source reservoirs for microplastics in the fall of 2023.There has been legislation activity at the federal level as Congress passed the Microbead-Free Waters Act of 2015 which prohibits the manufacture, packaging, and distribution of rinse-off cosmetic products that contain plastic microbeads. There are a number of actions in progress internationally, but one to keep an eye on is the United Nations Environment Assembly which passed a resolution in March 2022 that called for a legally binding international treaty to address the problem of plastic materials increasing in the environment. The first round of negotiations for the international plastics treaty was held in Uruguay in December 2022 with additional negotiations scheduled in 2023 and 2024.

With increasing attention comes the distinct possibility that regulations or guidelines will be established that change how we use plastic materials. What might we see as agencies get closer to establishing regulations for microplastics? For construction sites, best management practices (BMPs) to control sedimentation and erosion have been around for years. I anticipate that guidance forthe use, management, and proper disposal of plastic construction materials will be reevaluated. The concept of extended producer responsibility (EPR) wherein responsibility of management of waste is retained by manufacturers might be applied to construction materials. In Maine, legislation was passed in 2021 that formalizes EPR for plastic packaging.Another direction to watch is environmental, social and governance (ESG) reporting. Measures to reduce or eliminate microplastics release from work sites could be an item for future ESG metrics.

As we wait to see how regulations might change, there are steps that can be taken.A lot of good information is available about natural and sustainable building materials. Avoiding the problem of microplastics is another good reason to use them. Project site housekeeping can always be improved. Manufacturers of insulation boards often offer methodologies for cutting to size that minimize or capture the resulting dust. And finally, awareness helps.It used to be that waste plastic was just unsightly. Now we are learning more about how to best use and responsibly manage this material.