Microplastics and PFAS (per- and polyfluoroalkyl substances) have emerged as two of the most ubiquitous and concerning environmental pollutants in recent years. While research on each of these contaminants has been increasing, their co-occurrence and interactions are only beginning to be understood. Mounting evidence suggests that microplastics can act as carriers for PFAS, compounding their already significant environmental and health impacts.
What are Microplastics and PFAS?
Microplastics are tiny plastic particles less than 5mm in size that are now found in every corner of the globe – from the deepest ocean trenches to the air we breathe. They are created from the breakdown of larger plastic debris as well as manufactured for use in certain products like cosmetics. Common sources of microplastics include:
- Synthetic clothing fibers
- Vehicle tires
- City dust
- Road markings
- Marine coatings
- Personal care products
PFAS are a class of over 4,000 human-made chemicals used in a wide range of consumer products and industrial applications due to their water and oil repellent properties. They are found in items like non-stick cookware, stain-resistant fabrics, food packaging, and firefighting foams. PFAS are often called “forever chemicals” because they do not naturally break down in the environment.Some PFAS compounds, like polytetrafluoroethylene (PTFE) and polyvinyl fluoride (PVF), can themselves occur as microplastics. PFAS are also used as coatings on other plastic products that can degrade into microplastics over time. This creates a troubling intersection between these two contaminants.
Environmental and Health Impacts
Microplastics have contaminated the entire globe and every level of the food chain. Plastic particles have been detected in tap water, beer, salt, and seafood. A 2019 study estimated that the average person consumes up to a credit card’s worth of microplastic every week.The full health effects of microplastic ingestion are not yet known, but studies have linked it to inflammation, cell damage, and reproductive issues in marine life. There are concerns microplastics could have similar effects in humans. Microplastics can also adsorb other toxins and pathogens, potentially transporting them into living organisms.PFAS contamination is similarly far-reaching, with the chemicals being detected in the blood of people and wildlife worldwide. Exposure to certain PFAS is linked to various health problems including:
- Kidney and testicular cancer
- Thyroid disease
- Pregnancy complications
- Liver damage
- Immune system dysfunction
- Increased cholesterol
Growing research also indicates PFAS exposure can reduce the effectiveness of vaccines and potentially make COVID-19 worse. The manufacture and disposal of PFAS also has a climate impact, as the process emits potent greenhouse gases.
Microplastics as Carriers of PFAS
While the individual threats posed by microplastics and PFAS are significant, research now shows these pollutants are interacting in the environment in concerning ways. Several studies have found that microplastics can adsorb PFAS present in the environment, acting as carriers and vectors for these chemicals.A 2021 study published in the journal Water Research examined the interactions of PFAS and microplastics in a lake environment. The researchers found that the adsorption of PFAS was up to 259 times higher on microplastics deployed in the lake compared to virgin plastic in the lab. This suggests that organic matter and biofilms that develop on microplastics in the environment greatly enhance their ability to adsorb PFAS.Other research has shown that weathered or aged microplastics accumulate higher levels of PFAS and other contaminants compared to virgin microplastics. As plastic particles degrade in the environment, they can develop cracks and pits that increase their surface area. Chemical changes from UV exposure also make them more reactive. These factors make “old” microplastics potentially more hazardous.The adsorption of PFAS onto microplastics is influenced by factors like salinity, pH, and the specific properties of the plastic and PFAS in question. PTFE and PVF microplastics can also directly leach PFAS. This means a complex mixture of PFAS is likely hitching a ride on the microplastics that permeate our environment.This has implications for the transport and bioavailability of PFAS. Microplastics are readily consumed by filter feeders, fish, and other marine life, allowing any adsorbed contaminants to enter the food chain. A 2020 study found that the presence of microplastics enhanced the accumulation of PFAS in plant roots, meaning microplastics could affect uptake of PFAS on land as well.
Wastewater Treatment and Landfills: Hubs for PFAS and Microplastic Pollution
Wastewater treatment plants (WWTPs) and landfills have been identified as significant sources of both PFAS and microplastics in the environment. Many common PFAS, like PFOA and PFOS, are readily transported through the wastewater system to treatment plants. Conventional wastewater treatment is not effective at removing PFAS, resulting in their release to waterways in treated effluent or accumulation in sludge that may be land-applied.Similarly, WWTPs are not designed to capture microplastics, particularly those in the micro- and nano-size range. Microplastic fibers from clothes washing and microbeads from personal care products flow in large quantities to treatment plants. A 2016 study estimated that a single treatment plant discharged over 4 million microplastic particles into the receiving waters each day.Landfills are repositories for discarded plastics and PFAS-containing waste where these pollutants can slowly leach out over time. PFAS has been detected in landfill leachate at levels far exceeding safe drinking water limits. Microplastics have also been found in landfill leachate and groundwater near these waste sites.The co-occurrence of PFAS and microplastics in wastewater and landfill leachate provides opportunities for adsorption, meaning microplastics discharged from these sources to the environment are likely carrying a PFAS burden. Upgrading wastewater treatment to address both PFAS and microplastics is an urgent need.
The Challenge Ahead
The pervasive pollution of our environment with PFAS and microplastics presents an immense challenge. The research on how these contaminants interact is still emerging, but it’s clear that their combination magnifies the threat to ecosystems and human health.Solving this problem will require a multi-pronged approach, including:
- Restrictions on non-essential uses of PFAS and single-use plastics
- Holding polluters accountable for cleanup costs
- Developing better wastewater treatment and landfill management practices
- Advancing research on health effects and remediation methods
- Educating the public to drive behavior change
While the scale of PFAS and microplastic contamination is daunting, growing awareness and the development of promising solutions provide some hope. Innovative water treatment technologies, like advanced filtration membranes, may help curb the release of PFAS and microplastics. Efforts to hold manufacturers responsible, like recent lawsuits against PFAS producers, could shift the financial burden of cleanup to polluters.Increasing public awareness is also key. As more people learn about the dangers of PFAS and microplastics, consumer choices and political will for action will grow. While we can’t undo the damage already done, we can work towards a future with cleaner water, healthier ecosystems, and a non-toxic circular economy. Tackling the twin threats of PFAS and microplastics is central to achieving that goal.