The Macro-sized Problems Caused by Microplastics

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Plastics are such a part of our everyday life that we hardly notice how ubiquitous they have become. They are found everywhere, from food containers and clothing to car parts and medical equipment. Due to their versatility, durability, and low cost, global production and consumption of plastics have increased dramatically since the mid-20th century. The Organization for Economic Cooperation and Development (OECD) estimates that, without any intervention, global plastic use and associated waste will triple by 2060. Only about 10 percent of plastics are recycled after use, with the remainder ending up in incinerators, landfills, or the environment. The durability of the material means that plastics released into the environment persist for long periods of time, leading to substantial accumulation that is causing increased concern within the scientific community.

Sample of Microplatic particles found in the Chesapeake Bay Watershed
Source: Chesapeake Bay Program (Flickr; License: CC BY-NC 2.0)

Microplastics are small plastic particles, generally less than 5 millimeters in size, that occur in a wide range of shapes and materials. Most microplastics in the environment result from the degradation of larger plastic products either during use or after they have been discarded. Due to their small size, microplastics are easily transported by wind, water currents, and stormwater and have been found all over the world in the air, soil, and water, and human and animal body tissues and fluids. Scientists are learning more every day about the potential impact of microplastics on our health and environment.

Why are scientists concerned about microplastics? The impacts of microplastic contamination on both humans and the environment are not yet fully understood, but there is increasing evidence that microplastics can have adverse health effects on a wide range of organisms. When ingested by animals, microplastics can inhibit normal body functions and alter feeding behavior. An organism ingesting microplastics may feel full, even though it does not receive any nutrition from the microplastic material. This can lead to weakness and even starvation. Fibrous microplastics, such as those resulting from synthetic textiles, may present an entanglement hazard in certain environments. Certain microplastics may also be toxic, either due to the plastic polymer itself or due to the coatings, fillers, and other additives used. Additionally, microplastics can act as carriers for pathogens and other chemicals such as heavy metals and PFAS, or per- and polyfluoralkyl substances. Studies have also found a link between microplastics and various human health impacts, such as negative effects on reproductive health and fertility, increased risk of heart attacks or strokes, and increased risk of some types of cancer.

What is being done about microplastics? Without meaningful intervention, it is anticipated that plastic accumulation in aquatic ecosystems, in other environments, and in the tissues of organisms, including humans, will continue to increase. One way to reduce plastic pollution, including microplastics, is to reduce the use of plastic products. Other actions include better management of plastic waste at end of life, to prevent it from being released into the environment. Reducing plastic pollution will require action by a variety of stakeholders, including governments, businesses, academia, and consumers. It will also require action at all stages of the plastic life cycle, from preventing plastic pollution in the first place to improving waste management.

Microplastic particles litter the ground near a stormwater inlet at a plastic recycling facility
Source: Christopher Rua, PHE

Recent U.S. and global actions attempting to reduce the prevalence of microplastics in the environment include:

  • The Microbead-Free Waters Act of 2015, which amended the Federal Food, Drug, and Cosmetic Act, prohibits the manufacturing, packaging, and distribution of rinse-off cosmetics, including toothpaste, that contain plastic microbeads. Microbeads were often added to such products for the purpose of exfoliating and cleansing.

  • The Save Our Seas 2.0 Act was passed in December 2020 to address plastic accumulation in coastal ecosystems and communities. The Act strengthens the U.S. ability to respond to marine debris, enhances global engagement, and provides for new grants for and studies of waste management and mitigation. The Act directed the U.S. Environmental Protection Agency (EPA) to develop a national strategy on plastic pollution.

  • In November 2024, the EPA released the National Strategy to Prevent Plastic Pollution with input from the public as well as federal, Tribal, territorial, state, and local government entities. The strategy identifies actions to be taken to eliminate the release of plastic into the environment by the year 2040. Example actions include reducing single-use plastics, measuring the impacts of plastic pollution, and enhancing policies and incentives to reduce the generation of plastic waste.

  • Although an agreement has not yet been reached, negotiations to produce the first global, legally binding treaty on plastics pollution are also in the works. Negotiators from nearly 200 countries met in South Korea as recently as November 2024. For any proposal to be included in the treaty, all nations must agree to it. This round of negotiations did not result in a final treaty document, but participating countries agreed to resume talks next year.

Each year the USFWS, the State of Hawaii, and NOAA staff and volunteers collect tons of marine debris from the Papahānaumokuākea Marine National Monument in the Pacific
Source: NOAA (FLICKR; License: CC BY-NC 2.0)

Many states and counties have also started to take action, such as by banning the use of single-use plastic bags and Styrofoam food containers.

Our understanding of microplastics and their effects will continue to improve as increasing focus on the issue paves the way for greater scientific study. The environmental professionals of Potomac-Hudson Engineering, Inc. (PHE) stay abreast of the current issues facing our clients and emerging topics within the field. Recent PHE projects have sought to advance our knowledge in this area, including efforts by the International Joint Commission (IJC), a binational organization that seeks to advance U.S.-Canada cooperation on the management of transboundary waters.

PHE (with our teaming partner LimnoTech) recently completed work on a project for the IJC that focused on microplastics management in the Laurentian Great Lakes. The Great Lakes are the source of much of the earth’s freshwater and are home to a variety of unique ecosystems and a thriving economy. The IJC tasked the PHE team with conducting a literature review to assess the current state of knowledge regarding microplastic pollution in the Great Lakes, as well as current microplastic sampling and analysis techniques. PHE and LimnoTech also supported updates to an online database of microplastic ecotoxicology studies, facilitated two expert workshops on microplastic monitoring and risk management, and prepared a summary project report that will be made publicly available on the IJC’s website.

If you have questions regarding microplastics, the state of current research, or how PHE can help you with your project, reach out to Samir Qadir at samir.qadir@phe.com.