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PFAS and Microplastics are in Cahoots! – June 24

PFAS and Microplastics are in Cahoots!

Per- and polyfluoroalkyl substances (PFAS) and microplastics (MPs) sure seem like best buds! These two contaminant groups have monopolized the scientific news cycle in recent years. These days, we are inundated with the amount of environmental news shorts popping up phones and computer screens to warn people about the deleterious effects of household/consumer products all around us. If it is not in the air we breathe, it is in the things that we touch. If it is not in in our clothes, it is in our food. If it cannot be found in the things that we all strive to acquire, it can be found in the waste products that are created in the manufacturing of those things.

The abstract elements of risk and reward are around us and within us in ways that we cannot possibly imagine because attributes of our physical world have not yet been seen, found, or invented – whether by intention or pure accident. On every topic of science, civilizations of the past and present are forced to go to great intellectual measures to maximize the positives and minimize the negatives of the topic. Nowhere is this more apparent than in the world of environmental chemistry. It is our job as scientists to always be looking for the areas in chemistry that may need to be maximized or minimized.

The last 5-10 years have uncovered several cases in which PFAS are showing up in low levels (parts per trillion) in various municipality drinking water sources across the country. As has been covered in past issues of The Standard, these “forever chemicals” are known by-products of industry and consumer products such as nonstick cookware, waterproofing products, stain-resistant furniture coatings, and fire retardants, to name just a portion of the sources. Meanwhile, on a parallel coincidence, I have also been noticing more and more news regarding the increasing abundance of MPs. It is estimated that approximately 400 million tons of plastic are manufactured every year; this number also happens to be the estimated weight of all of humanity.(1,2)

The plastic that you see along the side of the road and perhaps along the beachfronts may be disturbing, but these visuals are just the tip of the “trashberg.” These plastics are known to break down into tiny segments that can be found in just about every ecosystem on the globe, and in the food we eat. MPs are minuscule plastic waste fragments or fibers measuring less than 5 mm in diameter, which is about the size of a pencil eraser tip to the size of a large bacteria, mainly in our oceans and waterways. They are insoluble in water and nondegradable. When looking for MPs we do not always need sophisticated instrumentation like we do when looking for PFAS, the larger pieces of MPs can clearly be seen with the naked eye.(1,3)

The Correlation between PFAS and MPs

Since several product sources of PFAS originally came for molecules used in the formation of some f plastics, it seemed logical to me to ask the question: Is there a correlation between PFAS and MPs? Or a more important question may be: Would it be prudent to focus our regulations on one more than the other? If we could theoretically reduce the amount of one by a large percentage would that action, in turn, automatically reduce the other contaminant by a “large enough” percentage to the point where consensus would call it a win for the environment?

A Toxic Relationship

Another question would be: Is there a combined toxicity (e.g., antagonistic toxicity) component that we should be more concerned about than simply looking at the individual toxicities of just PFAS or MPs?

One case for this reasoning would be that PFAS are found to easily adsorb onto biofilms found on the surfaces of MPs, even though the knowledge on this interaction and combined toxicity of PFAS and MPs is still fragmentary. A study conducted by Llorca et al. (2018) reported that the adsorption of PFAS generally increases with the increasing carbon-chain length of the PFAS. In addition, the polymer type of the MPs is important for the adsorption to take place. It has been found that the hydrophobicity of common MPs, and therefore the propensity for these groups to take on PFAS in adsorption, follows the general rule:

Polypropylene (PP) > Polyethylene (PE) > Polystyrene (PS; or Styrofoam) >

Polycarbonate (PC) > Polyvinyl chloride (PVC) (3)

Another case for this reasoning would be that in the natural world, we know that MPs probably serve as a vector for PFAS, thus altering the fate and transport of PFAS. In a large body of water, pristine MPs can act as carriers and increase the horizontal transport of PFAS to places where they may not normally be able to drift.(3) On the other hand, the aggregation and biofouling process can induce the sedimentation of MPs by making them stickier and promote heteroaggregation between MPs and organisms such as algae. This process increases the potential for sinking and creates a mechanism for vertical transport of the MP-PFAS particle – this ultimately leads to dispersion by organism excretion and food chain transfer at the bottom of the water body.(4)

Even though it may be found that the toxicological effects of PFAS and MPs are not magnified in an organism, studies show that the distributions and locations these of contaminants increase from not just one or two places inside the organism, but to several different places. For example, MPs are mainly accumulated in the gills and intestines of fish(3), whereas PFAS mainly accumulate in the blood, muscle, liver, and reproductive organs of the same fish. This may not increase the likelihood that a certain part of the body is put under toxic stress (i.e., gills), but it may increase the likelihood that the overall body is put under additional stress from having toxins in more regions of the organism.(4)

Here in the U.S., the Environmental Protection Agency (US EPA) has begun to embrace the idea that PFAS need regulation to some degree; however, there seems to be a larger body of research surrounding the PFAS family of chemicals than there is around MPs. A large reason for this is that it is probably easier to look at toxins on a molecular basis than to look at hundreds of chemicals in so many different varieties of large particles. As of 2023, the Microbead-Free Waters Act of 2015 is the only federal legislation aimed specifically at MPs; this legislation prohibits the use of microbeads in rinse-off cosmetics. To date, both the U.S. Food and Drug Administration (FDA) and the US EPA have endorsed extensive research into MPs, but neither have actually proposed regulation that spotlight MPs through pollution control, drinking water standards, food additives, packaging or food contact substance regulation.(5) This may change in the next decade as studies are increasingly showing that major groups of plastic materials (i.e., polyethylene, polypropylene, and polyethylene terephthalate) were shown to adsorb PFAS in real aquatic environments more than they would in laboratory settings.(4) These new findings are demonstrating the increasing need for more study to find the potential adverse effects of organisms exposed to MPs alone but also the need to consider the ramifications of MPs acting as a vehicle for transporting PFAS and other already-regulated chemicals into wider regions of the environment, places where they may not have navigated to without the MPs.

As reported in prior issues of The Standard, The US EPA has published a final rule that mandates reporting by manufacturers and importers of the more than 1,000 PFAS manufactured and imported in the U.S. since 2011 under the Toxic Substances Control Act (TSCA).(6,7) This final rule will require detailed interpretation across an entire business enterprise, as well as upstream sources and downstream end-users, as broadly described in the ruling. The new rule contains no volume exemptions and requires specific reporting of data by each reporting entity.

Although MPs are not up to the same legislative scrutiny of PFAS, the US EPA has released a “Draft National Strategy to Prevent Plastic Pollution.” This strategy could affect the regulated manufacturing community, especially those handling plastic wastes, or any industry that regularly uses plastics. As of this date, the three objectives to push for a circular economy are to 1) reduce plastics pollution during production, 2) improve post-use materials management, and 3) prevent trash and MPs from entering waterways and removing escaped trash from the environment.(6,8)




  1. Plastic, (micro)plastic everywhere. What does it do and why should we care?
  2. All Life On Earth, In One Staggering Chart:
  3. Interaction and Combined Toxicity of Microplastics and Per- and Polyfluoroalkyl Substances in Aquatic Environment:
  4. Perfluoroalkylated Substances (PFAS) Associated with Microplastics in a Lake Environment:
  5. Microbead Ban: The Microbead-Free Waters Act: FAQs | FDA
  6. From Particles to Policy: Microplastics at the Crossroads of Regulation and Litigation:
  7. The Interstate Technology Regulatory Council:  Chemicals in Artificial Turf Screening Research Update – Accessible
  8. We Inhale a Credit Card’s Worth of Microplastics Each Week: