PFAS Chemicals

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By Baylin Bennett, Masters Candidate at Emory University and Surfrider's Fall 2020 Science and Policy Intern

PFAS, or Per- and Polyfluoroalkyl Substances, are a large and diverse group of manmade chemicals used by industry to make a myriad of products from grease-resistant sandwich wrappers to firefighting foams. The popularity of PFAS chemicals led to their pervasive presence in the environment, which has put them under investigation for potential impacts to environmental, wildlife, and human health. And rightfully so, as studies are revealing worrisome findings, PFAS chemicals have been found in the blood of polar bears and bottlenose dolphins, and in crops and drinking water of homes near manufacturing sites, such as those throughout the Cape Fear River Basin in North Carolina. Further, certain PFAS chemicals are now associated with negative human health impacts such as liver damage and pregnancy-induced hypertension and preeclampsia. Yet despite these findings, little has been done to regulate this family of chemicals.

Read below to learn more about PFAS, including their chemical background, prevalence in the environment, ways to avoid them, current polices being proposed to address them, and more!


Introduction

With over 8,000 members, Per- and Polyfluoroalkyl Substances (PFAS) are an expansive family of man-made chemicals popular for their ability to enhance the durability and lifespan of a wide range of products, including to-go food containers, paints, cosmetics, and more. PFAS form fluoropolymers that create durable plastic coatings, giving everyday items properties such as heat-resistance, water-resistance, and the ability to be non-stick.[1] [2] [3] PFAS chemicals have an abundance of applications and, therefore, are used in many products. However, within the last couple of decades, some PFAS chemicals have been associated with negative impacts on the environment, wildlife, and human health. Contaminated drinking water can be one of the primary sources of exposure to PFAS chemicals, such as is the case for over 1.5 million residents in the Cape Fear River Basin region which will be discussed in more detail later.[4] The entire PFAS family was brought under scrutiny when their negative impacts were considered with their wide use in applications, their ability to release and persist in the natural environment and waterways, and their continued exposure to humans and wildlife. This article provides a summary of what PFAS are, what products and applications they are primarily used in, a summary of impacts their exposure can cause to humans and wildlife, and policy options for preventing the use and release of PFAS.

PFAS Chemical Properties and Family Background

In the late 1930s, the DuPont Chemicals Company created the first known PFAS chemical, a polymerized form of tetrafluoroethylene gas, called polytetrafluoroethylene (PTFE). PTFE is now known as Teflon®. In 1946, DuPont put its first Teflon® products on the market.[5] Since then, PFAS chemicals have been used to make a variety of products. Before exploring the PFAS family’s many uses, understanding how the family of chemicals is organized will be helpful. The following information describing the PFAS family’s chemical structures is a summary of a scientific review authored by international and US federal health agencies and industry leaders, such as DuPont, and was funded by PlasticsEurope and PLASTICS.[6]

Picture1.jpg
Figure 1. PFAS Family Tree Depicting Some of the Family Members Addressed In This Article. It is important to note that there are nearly 8,000 PFAS chemicals.

Polymers and Nonpolymers

The PFAS family contains two main groups: polymers and nonpolymers. A polymer, “poly-” means “many”, and “-mer" refers to a “segment, is a compound that repeats the same segment structurally. The most iconic PFAS polymer is Teflon®. Nonpolymers are compounds that do not contain repeating segments. They are typically used to create polymers. An easy way to visualize the difference between polymers and nonpolymers is to use Legos®. Take 3 Lego bricks: a red one, a yellow one, and a blue one. Each of these bricks represents a different nonpolymer compound - the color of the brick makes them different from each other. If they are stacked on top of each other in any color order, a new, more-complex nonpolymer compound is formed. Now, take 3 identical copies of that new nonpolymer compound. When those 3 copies are connected or bonded, a polymer is formed. See the figure below for a visual illustration.

Figure2.jpg
Figure 2. A Graphical Illustration of Polymers and Nonpolymers.

The Difference Between Per- and Poly-fluoroalkyl Substances

The PFAS family includes both perfluoroalkyl substances and polyfluoroalkyl substances, which can be nonpolymers (e.g. PFOS and PFOA) and polymers (i.e. fluoropolymers). Generally, perfluoroalkyl substances are chains of carbon atoms where all of the hydrogen atoms that were attached to carbon atoms have been replaced by fluorine atoms. Polyfluoroalkyl substances are chains of carbon atoms where all of the hydrogen atoms attached to at least one carbon atom, but not all of the carbon atoms, have been replaced by fluorine atoms. The prefix “per-” means “all” and the prefix “poly- means many. “Alkyl” refers to the exchanging of the hydrogen atom for a fluorine atom. Taken together, perfluoroalkyl substances are substances where all hydrogen atoms bonded to carbon atoms have been replaced with fluorine atoms. Similarly, polyfluoroalkyl substances are substances where many hydrogen atoms have been replaced with fluorine atoms. Below is a visual way to understand these definitions:

Figure3.jpg
Figure 3. Visual Representation of Perfluoroalkyl and Polyfluoroalkyl Definitions.

Although those definitions might be difficult to understand, they provide a key insight into why PFAS chemicals are successful and widely used in many applications. The carbon-fluorine bond is considered to be “the strongest bond in organic chemistry”.[7] This bond is the main staple of PFAS chemicals and translates practically to a physically durable, strong product. It is the very reason why the PFAS family has been given the moniker “Forever Chemicals”. The structural foundation that PFAS chemicals are built with has an innate ability to resist degradation (e.g. they are heat-resistant, water-resistant, and nonstick). While this is an admirable quality in products, its persistence can cause notable concerns once introduced into the environment.

Long and Short-Chain Varieties

The PFAS family is also classified into long-chain and short-chain chemicals. Long- and short-chain PFAS chemicals are manufactured intentionally but short-chain PFAS chemicals can also be byproducts of the environmental degradation of other PFAS chemicals. The word “chain” refers to a group of the same element connected in a row. Chains can either form the backbone of a chemical or “branches” called side-chains on a chemical. With PFAS chemicals, long-chain and short-chain refers to the length of their carbon-chain backbones.

Long-chain PFAS chemicals usually have 6 or more carbons in a chain.[8] The most well-known long-chain PFAS chemical group is the “C8” group, which are 8-carbon-chain PFAS chemicals and include PFOA and PFOS. The C8 group was made infamous in the 2017 class-action lawsuit against DuPont, 3M, and other large manufacturers of the C8 PFAS chemicals.[9] The story behind this lawsuit was turned into a movie in 2019 titled Dark Waters.[10] The research that led to this lawsuit demonstrated negative human health associations from both PFOA exposure, which was an ingredient in 3M’s famous Scotchguard® products, and PFOS exposure, which was an ingredient in DuPont’s Teflon®-making process.[11] Additionally, lawsuits regarding C8 PFAS chemicals are still being filed as of 2020.[12] Now, banned from production and use in the US, PFOS and PFOA have been replaced by similar functioning PFAS members. The most notable replacement is GenX®, which is a short-chain PFAS chemical produced by a DuPont company called Chemours.[13]

Short-chain PFAS chemicals generally have less than 6 carbons in a chain. The most common short-chain PFAS chemical group is known as the “C4" group. Short-chain PFAS chemicals were introduced as a “safer alternative” to long-chain PFAS for four main reasons. First, it was believed that short-chain PFAS chemicals could not break down into PFOS or PFOA. Secondly, they were believed to be difficult to absorb yet easy to eliminate from the human body. Thirdly, they supposedly do not bioconcentrate or bioaccumulate. Finally, they allegedly showed low toxicity in mammals and the environment.[14] However, studies later found that certain short-chain PFAS chemicals actually can accumulate in the organs of both humans and wildlife.[15] [16] Additionally, some were found to be highly persistent and mobile in the environment.[17] Lastly, it is believed that even if humans could metabolize and eliminate short-chain PFAS chemicals faster than long-chain ones, continual exposure to short-chain PFAS chemicals would negate the benefits of the short processing time.

PFAS Contamination and Sources of Exposure

Exposure to a chemical can be characterized in two different ways: an exposure pathway and an exposure route. In terms of human health, an exposure pathway is an environmental pathway a chemical takes to get to its source location, a human. For example, a PFAS chemical could be released into the air by the manufacturing plant. It falls out of the air into a nearby lake during a rainstorm. Then it enters a fish in the now-contaminated lake, which is then caught by a fisherperson. This is one example of an exposure pathway. The other mechanism, an exposure route, is how a chemical enters the human body. There are four main exposure routes: ingestion, inhalation, absorption, and injection. For PFAS chemicals, all but injection have been demonstrated to be possible exposure routes (see the figure below).

Chms-ecms-500x423-eng.jpg
Figure 4. Chemical Exposure Diagram. Graphic sourced from Health Canada.[18]

Ingestion can include both eating and drinking contaminated substances, either voluntarily, such as eating a contaminated meal, or involuntarily, such as accidentally swallowing contaminated lake water when swimming. To finish out the previous example, the route of exposure to that fisherperson, who caught the contaminated fish in the lake that was contaminated by PFAS chemicals falling during a rainstorm, would be ingestion if they ate the fish. For PFAS chemicals, there are many documented exposure pathways that could lead to PFAS entering a human body.

Michigan DEQ PFAS.png
Figure 5. Examples of PFAS Exposure Pathways. Graphic sourced from the Michigan Department of Environment, Great Lakes, and Energy.[19]

Due to the versatility and persistence of PFAS chemicals, personal exposure sources are widespread. According to US federal agencies, personal exposure routes for PFAS chemicals include:[20] [21] [22]

  • Mother to fetus from fetal exposure in utero across the placenta via cord blood
  • Mother to infant from infant consumption of breastmilk from a mom who has PFAS chemicals in her body
  • Ingesting water (municipal, well, and bottled) or food (such as fish and plants) from a contaminated source
  • Inhaling or ingesting contaminated soil or dust
  • Eating food packaged in products where PFAS chemicals were used
    • Examples include pizza boxes, microwavable food packaging, and to-go packaging
  • Using certain non-stick cookware, stain-resistant carpeting, and water-repellent clothing
  • Working in manufacturing plants that produce or use PFAS chemicals
    • Examples include chrome plating, electronics manufacturing, and oil recovery


Ingesting contaminated drinking water is the primary exposure route for PFOS and PFOA according to the US Department of Health and Human Services’ National Toxicology Program[23]. PFOS and PFOA, which are part of the C8 group of long-chain PFAS chemicals, are two of the most studied members of the PFAS family of chemicals.[24]

Contaminated sites are typically found around the vicinity of manufacturing plants that use PFAS chemicals, military bases (currently used and deserted), and airports. Airports are common places where firefighters conduct training scenarios using aqueous film-forming foam (AFFF), which traditionally relies upon certain PFAS chemicals to extinguish fires.[25] [26]

Figure 6. PFAS Contamination in the United States of America. Graphic sourced Environmental Working Group.[27]
Figure 6. PFAS Contamination in the United States of America. Graphic sourced from the Environmental Working Group.[28] Click here to visit their interactive PFAS map!

PFAS Use In Industry and Products

PFAS chemicals are popular for their many abilities and applications. These chemicals are employed by a wide range of users from governments and militaries to everyday individuals. In 2015, the Swedish Chemicals Agency, KEMI, reported there were probably around 3000 PFAS chemicals on the market globally.[29] Below is a list of item genres that often rely on PFAS chemicals for production and use.[30]22 [31] [32]20 This non-exhaustive list is composed of different variables that make up possible exposure pathways for PFAS chemicals.

  • Cleaning products
  • Hygiene products (shampoo, dental floss, etc.)
  • Cosmetics (makeup, nail polish, etc.)
  • Paints, sealants, and varnishes
  • Dairy product cartons (milk, yogurt, etc.)
  • To-go foodware containers (sandwich/burger wrappers, food containers, etc.)
  • Take-out accessories (utensils, napkins, bowls, bags, etc.)
  • Microwavable food packaging
  • Stain-resistant carpets/rugs and furniture (pre-applied and self-use sprays)
  • Nonstick cookware (Teflon)
  • Automotive applications such as waxes and paints
  • Fire-fighting foams (fire department, personal extinguishers, etc.)
  • Oil recovery
  • Electrical wire casing/housing
  • Contaminated food and drinking water


PFAS Safety and Advisory Levels

Because of their many continued uses and previous releases into the environment, some PFAS chemicals are increasingly being studied to determine their potential negative impacts on the environment, wildlife, and humans. As explained earlier in this article, PFAS chemicals contain a very strong, stable bond called a carbon-fluorine bond. The strength of this bond protects the PFAS chemical from quick degradation, allowing it the potential to accumulate wherever it winds up. Presently, it is believed that not all PFAS chemicals have this ability. It is known, however, that some PFAS chemicals do have the ability to bioaccumulate and, consequently, biomagnify up the food chain.[33]3 [34]19 Bioaccumulation is the accumulation of a chemical in a human or animal upon consumption (inhalation or ingestion) of a contaminated substance. Biomagnification is bioaccumulation up trophic levels, or up a food chain. When PFAS chemicals enter water sources, the fish and other aquatic life in the contaminated water body can become contaminated; this is called bioconcentration. Humans can consume the contaminated fish and water, putting themselves at risk for contamination. The movement of PFAS chemicals from water to fish to humans is an example of biomagnification. So, if PFAS chemicals are difficult to break down and can accumulate in the environment, wildlife, and humans, just how long do they linger?

One way to measure environmental persistence, or lingering, is referred to as a half-life. A chemical’s half-life is the duration required for half of the chemical concentration to degrade. A chemical’s half-life is dependent on many factors including the size of the chemical (e.g. amount of carbons in the chain), the complexity of the chemical (e.g. amount of functional groups or side-chains), as well as factors such as which species is being assessed. As shown in the table below, the half-lives of PFAS chemicals vary tremendously within one species as well as among other species.

Table 1. Estimated Half-Lives for Five PFAS Chemicals In Different Mammalian Species. Table sourced from the US CDC’s Agency for Toxic Substances and Disease Registry.[35]
Table1.jpg

Short-chain PFAS chemicals, such as GenX, were introduced as a supposedly safer alternative to long-chain PFAS chemicals, but studies have found that short-chain PFAS chemicals can accumulate in other organs. Both chains are highly persistent, or stable, and mobile in the environment.[36] As will be described later, certain PFAS chemicals were demonstrated to have negative effects on the immune system, reproductive system, endocrine system, and other organ systems. If some PFAS chemicals have been linked to negative health effects, is there a level that is acceptable to be exposed to? Unfortunately, just as PFAS chemical half-lives are complicated, the US federally-set acceptable levels of PFAS chemicals have proven to be challenging as well. This is due to several reasons including the fact that they are federally non-enforceable values. The following section will briefly cover important US safety levels regarding PFAS chemicals.

Health Advisory Level (HAL)

A Health Advisory Level (HAL) pertains to drinking water contamination. The US EPA defines a HAL as “a non-regulatory health-based reference level of chemical traces (usually in ppm) in drinking water at which there are no adverse health risks when ingested over various periods of time”.[37] In other words, HALs are lifetime personal reference levels, rather than federally enforced ones, that suggest the lifetime drinking water consumption concentration for a chemical at which point should not cause harmful effects if consumed. These levels address a scenario of chronic, repeated exposure to chemicals via drinking water. HALs are usually listed in units called “parts per million”. Parts per million (ppm) is a common unit of measurement that means in 1,000,000 parts of a substance (i.e. gas, liquid, solid), there are “X” parts of a chemical. For PFOS and PFOA, the only two PFAS chemicals that have been given health advisory levels, the unit of measure is in parts per trillion (ppt). The PFOS and PFOA health advisory levels were changed from the 2009 levels of 200ppt and 400ppt, respectively, to 70ppt for both chemicals in 2016.[38] [39] This means that for every one trillion parts of drinking water only 70 parts should be either PFOS or PFOA (or a total mixture of both) to avoid the potential for harmful effects. The US EPA cites an advancement in the understanding of PFAS chemicals as the reason behind this drastic change.[40]

Minimal Risk Level (MRL)

A Minimal Risk Level (MRL) pertains to consumption levels. Consumption includes the exposure routes ingestion and inhalation. According to the US CDC’s Agency for Toxic Substances and Disease Registry, an MRL is “an estimate of the amount of a chemical a person can eat, drink, or breathe each day without detectable risk to health”.[41] MRLs are of special importance because they consider age as a factor for exposure level. As shown in the table below, the MRLs for children are roughly 4x those suggested for adults for each listed PFAS chemical.

Table 2. Minimal Risk Levels for PFAS in Drinking Water. Table sourced from the Agency for Toxic Substances and Disease Registry. [42]
Table2.jpg

Recall that the HAL drinking water suggestions for PFOS and PFOA were both 70ppt. When compared to the above table of MRLs, not only do the adult levels differ from the HALs, 70ppt is not considered to be a safe level for children. It is important to note that MRLs are not federally regulated either. In fact, there are no US federally regulated levels for PFAS chemicals. Some PFAS chemicals are banned from manufacturing and use such as PFOS and PFOA, while other PFAS chemicals are not. Regarding food products, there are currently no federal labeling requirements to warn consumers that items may contain PFAS. Further, the Biodegradable Products Institute (BPI), which is an independent certifying organization that helps set self-regulated chemical safety level recommendations for companies making and using biodegradable products, has set the limit on PFAS levels in foodware at 100ppm of fluorine.[43]

California Safety Levels

The California Water Boards created two of their own state-set safety levels, called Notification Levels and Response Levels. A Notification Level (NL) is a “nonregulatory, precautionary health-based measure for concentrations in drinking water that warrant notification and further monitoring and assessment”. In August 2019, California Water Boards lowered the NLs for PFOS to 6.5ppt and PFOA to 5.1ppt.[44] In contrast, a Response Level (RL) is a level at which a chemical exceeds the California-set required level, thus mandating the water supplier or system “to take a water source out of use, treat the water delivered, or provide public notification”.[45] Recently in February 2020, California Water Boards lowered the RLs for PFOS to 40ppt and PFOA to 10ppt.[46]


Other Safety Levels

Before any safety levels were set for PFAS chemicals, they were - and most still are - used without any restrictions. According to a literature review published in 2016, all peer-reviewed scientific PFAS research published since 2002 has only focused on less than 10% of all known PFAS chemicals.[48] The review found PFOA research accounted for almost 20% of those articles, which was the most. PFOS came in second place, accounting for 16% of the publications. PFNA accounted for the third most with 7% of the publications. Although only a small portion of the PFAS chemicals have been studied to some extent, some of the findings suggest the whole PFAS family should be looked at closer. With this in mind, what are the known impacts PFAS chemicals can have on environmental, wildlife, and human health?

The Impacts of PFAS Exposure and Contamination

*Disclaimer: The purpose of the following section is to provide information on unanimously accepted data. Because the majority of research has been conducted on a handful of PFAS chemicals, each listed effect will be matched with the specific PFAS chemical(s) it is linked to. This section does not mean to insinuate that what has been shown to be true of the specifically-mentioned PFAS chemicals can be assumed to be true of the other 8,000+ PFAS family members. Rather, its purpose is to bring awareness to what is known and to argue that more PFAS chemicals should be studied.

Environmental and Wildlife Impacts

PFAS chemicals are widely used for their numerous useful applications. One of their most common uses in the environment is as flame retardants in firefighting foams. With wildfires on the rise, flame retardants are becoming a necessary tool to prevent spreading fires. This, along with other common PFAS applications, has created a dilemma for environmental and wildlife health. Two formerly popular PFAS chemicals, PFOA and PFOS, are persistent environmental chemicals due to their ability to bioconcentrate, bioaccumulate, and biomagnify. These abilities allow for PFAS chemicals to potentially increase in toxicity over time. Considering the popularity of PFAS chemical applications and their ability to move and persist in the environment, what is known about the toxicological PFAS chemical impacts on the environment and wildlife health?

Environmental Impacts and Prevalence
Mobility
A subset of PFAS chemicals called perfluoroalkyl acids (such as PFBS, PFBA and PFHxA) were shown to be highly persistent, or stable, and mobile in the environment.[49] This suggests that humans could be at higher risk of exposure to these PFAS chemicals than previously thought.

Vegetation
GenX was detected in grass (1-27ppt) and leaves (4.3-86ppt) within 3km of a Teflon plant in the Netherlands, suggesting uptake of GenX and other PFAS by locally grown crops and foods is possible.[50]

Drinking Water and Groundwater
GenX (1.4-8ppt) and PFOA (1.9-7.1ppt) were detected in drinking water in the Netherlands.[51] Even with currently used drinking water technologies, Genx is more difficult to remove from drinking water than PFOA, which is the PFAS GenX has replaced. Additionally, the average concentration of GenX in water samples prior to processing that were taken from a wastewater treatment plant located downstream of the Fayetteville Works plant in the Cape Fear River Basin measured 631ppt. After water processing, the samples still contained an average of 500ppt.[52] This study suggests that humans are possibly being exposed to GenX at higher levels than PFOA in drinking water. This contamination of the Cape Fear River watershed, a main source of drinking water for over 1.5 million people, will be discussed in more detail later.

A joint study conducted by the USGS and US EPA found PFAS chemicals in every sample collected from different drinking water facilities around the United States. Individual PFAS concentrations ranged from 1ppt to over 1100ppt. Additionally, removal of PFAS at these sites was overall poor. The average total PFAS concentration in water prior to treatment was 24.1ppt, whereas after treatment the average was 19.5ppt.[53]

PFBA-contaminated irrigation water in Minnesota was found to be the main source of PFBA in home-grown produce, such as tomatoes, cucumbers, squash, apples and raspberries.[54] This also suggests that PFAS chemicals can accumulate in produce and crops grown in exposed environments.

In a 2018 PFAS sampling report commissioned by NASA for their Goddard Space Flight Center at the Wallops Flight Facility in Wallops Island, Virginia, both PFOS and PFOA were found to exceed the recommended health advisory level (HAL) of 70ppt at certain monitoring and observation wells, as well as at some of Chincoteague’s production wells.[55] Chincoteague is a neighboring town to the NASA flight facility. Observation and monitoring wells are commonly used around the perimeter of facilities that use hazardous chemicals for the purpose of monitoring for potential leakage of those chemicals from the facility into the local groundwater. Production wells are wells that are used to remove oil or gas from underground repositories.

Wastewater
Strawberries and lettuce irrigated with reclaimed water at the Colorado School of Mines showed bioaccumulation of PFBA, PFHxA, and PFHpA concentration - all short-chain PFAS chemicals.[56] High concentrations of side-chain PFAS chemicals, which were used to manufacture Scotchgard™ fabric protectors both before and after the 2002 European ban, were found in biosolids at wastewater treatment plants in Canada. Biosolids are commonly used as fertilizers due to their nutrient-rich state.[57] Together with the previous findings, this highlights an overlooked area of possible human risk for PFAS chemical exposure.

Rivers
In China’s Yellow River, which is the 6th longest river system in the world, short-chain PFAS chemicals made up nearly 90% of PFAS chemicals measured in some samples. Additionally, overall long-chain PFAS chemicals predominately accounted for the PFAS chemical concentrations in suspended particulate matter and sediment. Finally, the study estimated that nearly 4 tons of the 11 PFAS chemicals they assessed flow through the Yellow River annually.[58]

Nine long-chain PFAS chemicals and five short-chain PFAS chemicals were found to bioaccumulate, bioconcentrate, and biomagnify in the foodweb of the second largest river basin in North Carolina, the Yadkin-Pee Dee River, which spans North and South Carolina and eventually releases into the Atlantic. Some concentrations were found to reach nearly 1700ppt. Additionally, the authors suggest a potential for maternal transfer of PFAS chemicals.[59]

Wildlife Impacts
Mammals
A subset of PFAS chemicals called polyfluoroalkyl sulfonates were identified as increasing in accumulation in the blood serum of polar bears from 1984 to 2014 in the Beaufort Sea, as well as other harmful chemicals including PCBs and chlorinated aromatics. Researchers hypothesized that nearby economic hubs in China would be the source of this high concentration of PFAS chemicals. Potential impacts of PFAS exposure include “adverse reproductive, development and systemic effects”.[60] In polar bears from eastern Greenland, the presence of both perfluoroalkyl sulfonates and polyfluoroalkyl carboxylic acid correlated with an increase in neurotransmitter levels, which indicates the potential for toxic effects on their cognitive processes and motor function.[61]

In Atlantic bottlenose dolphins, several PFAS chemicals (PFOA, PFOS, and PFDA) were associated with many immunological parameters, suggesting that these specific PFAS chemicals may cause negative impacts on bottlenose dolphin immune, kidney, and liver function.[62] Together with the previous two studies, PFAS chemicals are clearly present in places their use and presence were not intended for.

Fish
Similar results were observed from PFBS exposure in female (but not male) medaka, a fish native to East and South Asia. Additionally, the authors found this PFBS accumulation caused visual function impairment.[63]

Amphibians
PFOS and PFOA exposure decreased neurotransmitter levels in Northern leopard frogs, a species native to North America.[64] Neurotransmitters are vital for proper brain function. PFOS, PFHxS, PFOA, PFHxA, and PFPeA were found to accumulate in Northern leopard frog brains and cause “complex neurotransmission alterations”.[65]

Invertebrates
Bioaccumulation of PFOS, PFOA, PFNA, PFDA, PFUdA, PFDoA, and PFTrDA was found at differing levels in earthworms living in biosolid amended soil.[66] Biosolid amended soils are commonly used as nutrient-rich fertilizers. This study suggests that crops and produce are not the only unintended target of PFAS chemicals in the environment.

Human Health Impacts

With the aforementioned exposure pathways of the PFAS family in mind, taken together with their environmental persistence just discussed, what are the known human health impacts of exposure to these chemicals?

In 1956, Stanford University published a study showing that PFOA binds to a protein in human blood serum called albumin.[67] This was the earliest known study showing that a PFAS chemical can circulate in the human bloodstream. In April 2020, a study, published out of the Medical University of Vienna, expanded that list to include other common PFAS members, such as PFOS, PFOA, PFHxS, PFNA, and PFDA in human plasma.[68] Although only 5 of the over 8,000 PFAS family members were shown to have this affinity, the five that were observed all had different chain lengths as well as the most common functional groups found in the PFAS family. The authors suggest a similar finding could be seen in the other members because the five that showed this ability were considered a good representative sample of the entire family. Binding to human serum albumin (HSA) is an important feature to note because albumin is a common target for the biological delivery of drugs developed by the pharmaceutical industry. This is due to the size of and copious binding sites on albumin, as well as its ability to migrate to every organ in the body.[69] In other words, binding to HSA allows the chemical (eg, drug, PFAS chemical, etc.) to travel through the bloodstream and enter different organs in your body. PFAS chemicals have been observed “in the serum of workers, residents living near PFAS facilities, and the general population”.[70] In a 2011 study, the US CDC found PFOS, PFOA, PFNA, and PFHxS levels in 95% of people they surveyed.[71] Interestingly, a follow-up study showed a greater than 60% decrease in PFOA levels and a greater than 80% decrease in PFOS levels in their blood serum samples from between 1999 and 2014. They argue that this is correlated to the decrease in PFOA and PFOS production.[72]60 But what does the literature have to say about PFAS contamination effects?

In 2018, an extensive 852-page scientific review was published by the US CDC’s Agency for Toxic Substances & Disease Registry (ATSDR). This review summarized all known scientific findings regarding the impacts of PFAS chemicals on human health. The review is quick to explain that most of the results should be taken cautiously as they were conducted using cross-sectional studies. This means their results cannot be used to biologically-link PFAS contamination to direct causation of morbidity. Instead, the review findings can be interpreted as several PFAS chemicals have a suggested association with several negative effects in the human body, such as in the liver and on organ systems like the cardiovascular system, endocrine system, immune system, reproductive system, and developmental system. Below is a non-exhaustive list of the ATSDR’s 2018 review findings:[73]

  • Pregnancy-induced hypertension/preeclampsia (PFOA, PFOS)
  • Liver damage, as evidenced by increases in serum enzymes and decreases in serum bilirubin levels (PFOA, PFOS, PFHxS)
  • Increases in serum lipids, particularly total cholesterol and low-density lipoprotein (LDL) cholesterol (PFOA, PFOS, PFNA, PFDeA)
  • Increased risk of thyroid disease (PFOA, PFOS)
  • Decreased antibody response to vaccines (PFOA, PFOS, PFHxS, PFDeA)
  • Increased risk of asthma diagnosis (PFOA)
  • Increased risk of decreased fertility (PFOA, PFOS)
  • Small (<20 g or 0.7 ounces per 1 ng/mL increase in blood perfluoroalkyl level) decreases in birth weight (PFOA, PFOS)


Case Study: GenX Contamination In The Cape Fear River Basin

Let’s look at a currently ongoing case of PFAS contamination in North Carolina that is eerily familiar for many places around the US and the world. North Carolina has a storied history with PFAS contamination. The Cape Fear River is a vital source of drinking water for over 1.5 million people.[74]4 At a meeting with both local and state officials in 2017, officials from The Chemours Company revealed that their Fayetteville Works plant, formerly owned by their parent company DuPont Chemicals Company until 2015, had been discharging a PFAS chemical called GenX into the Cape Fear River system since 1980.[75] At that time, they were not producing GenX for manufacturing purposes. Rather, GenX happened to be a byproduct from other PFAS chemical manufacturing processes.

To further complicate the issue, NC DEQ officials discovered that The Chemours Company failed to disclose GenX as a potential discharge chemical in their National Pollutant Discharge Elimination System (NPDES) permit application. The NPDES permit allows companies to “discharge a specified amount of a pollutant into a receiving water under certain conditions”.[76] [77] This failure to disclose GenX as a discharge chemical led to the suspension of their NPDES permit.[78]64 Although this was encouraging to some, many residents were left confused about why a company would be ordered to stop discharging a chemical that they were told was “safe” by the company officials. Since this 2017 awakening of the GenX crisis in North Carolina, research has been conducted attempting to detail how extensive the contamination was - and still is - in the water systems across North Carolina.

Prior to the 2017 Chemours confession, a 2016 study identified GenX as one of the “important drinking water contaminants in the Cape Fear River Watershed of North Carolina”.[79]44 The study found that the average concentration of GenX in unprocessed water at a drinking water treatment plant (DWTP) downstream of the Fayetteville Works plant was 631 ng/L in 2013. 631ng/L is equivalent to 631 parts per trillion (ppt). In October 2018, the North Carolina Department of Health and Human Services (DHHS) officially set the “provisional drinking water health goal” for GenX at 140ppt.[80] One month later, the US EPA set their preliminary suggested lifetime reference dose for GenX at 80ppt.[81]63 In other words, the levels measured in the study were 4.5 times the DHHS health goal and nearly 8 times the soon-to-be recommended US EPA level. When GenX levels were assessed in water that had finished the treatment process at the DWTP, GenX was still present at a concentration of nearly 500ng/L, or 500ppt. Ultimately, the authors concluded that GenX was more difficult to remove from drinking water than PFOA, which was the chemical GenX was replaced on the market.

This study, along with others, led the Chemours Company to sign a Proposed Consent Order (PCO) issued by the North Carolina government in 2019.[82] The PCO, which is still in effect today, requires strong, important steps The Chemours Company must follow, including the prohibition of discharging “any process wastewater from the Facility” into the Cape Fear River, the elimination of 99.99% of all PFAS air emissions by routing air emissions to a thermal oxidizer by the end of 2019, and immediate “accelerated remediation of water [especially groundwater] flowing from the Facility to the Cape Fear River”. In other words, The Chemours Company can no longer dump their wastewater into the Cape Fear River, they can no longer emit any PFAS into the air, and they are required to remove the PFAS pollution from the groundwater beneath their facility that has been leaking into the Cape Fear River. Despite the seemingly big step forward, what is known about the GenX effects on human health since North Carolina residents have been exposed to this chemical for more than 30 years from their drinking water?

Unfortunately, there is not enough research conducted yet to accurately understand how GenX impacts human health. That said, studies in laboratory animals have shown that GenX causes damage in the “kidney, blood, immune system, developing fetus, and especially in the liver following oral exposure”.[83] As a reminder, “oral exposure”represents several types of exposure routes such as inhalation of contaminated air and ingestion of contaminated food or liquids.[84]18

These restrictions placed on The Chemours Company, which will likely be used as an outline for similar situations in the future, mark a very important step towards progress, but understanding the true situation of PFAS contamination in North Carolina still has a ways to go. Between November 2017 and May 2018, one study found that despite Genx not being present, four other PFAS chemicals (PFOS, PFOA, PFHxS, and PFNA) were measured in the blood serum of more than 97% of the Wilmington residents who participated at levels that exceeded the national levels.[85] As a reminder, both PFOA and PFOS have been banned from use since about 2006. If you or a loved one live in the Cape Fear River watershed region and are concerned about your potential for GenX contamination, please visit the NC DEQ website for more information such as whether you qualify for getting your well tested.[86]

Sadly, the Cape Fear River disaster is not the only tragic PFAS story in the US. This story inspired a similar investigation into a DuPont plant in the Ohio River Valley.[87] In Marinette County, Wisconsin, Tyco is being investigated for contamination from their fire training center that led to increased PFAS levels in local drinking water.[88] The state of New Jersey is suing Solvay for withholding information regarding the pollution from their West Deptford plant.[89] These are only some of the other stories from around the US. When you consider PFAS use globally, the number of stories similar to these from the US exponentiates. These stories about the prevalent misuses of PFAS chemicals inspire plenty of misconceptions. Let’s take a look at some of the common myths around PFAS chemical contamination.

Debunking Myths Around PFAS Contamination

PFAS chemicals make up a large family with over 8,000 members. They are used pervasively in society for their many applications, which gives everyday products important, helpful properties such as heat-resistance, water-resistance, and stick-resistance. The issue is a big portion of the PFAS family members that have been studied have been associated with problematic health outcomes for humans, wildlife, and the environment. They have also been shown to bioaccumulate, bioconcentrate, and biomagnify in the environment. Although only a small portion of the PFAS chemicals have been studied, the findings have begun to raise an alarm on the other members that are being manufactured and used without any sort of regulation and without extensive research on potential impacts. Before addressing ways to avoid PFAS chemical contamination, here are a few commonly believed myths regarding the PFAS family.

Myth #1: “PFAS chemicals can be removed from foods simply by washing them before eating them.” Likewise, “PFAS chemicals can be removed by cooking the food prior to eating it.”

Truth: The US FDA says “PFAS cannot be removed from foods by washing or cooking. The levels of PFAS that have been found in foods from the general food supply, however, are very low and based on the best available current science, the FDA has no indication that these present a human health concern”.[90]24

Myth #2: Food containers and utensils, such as what is used in some fast-food restaurants, are made without using PFAS chemicals.

Truth: The US FDA allowed 69 PFAS compounds to be used in food packaging products, including bags and bottles. Additionally, there are 62 PFAS chemicals approved for use in food by the FDA. Due to their ability to repel water and oil, PFAS chemicals have even been found in compostable “all-fiber” bowls including the ones used by the popular eatery Chipotle. For more information, read this article.[91] Recently though, in July 2020, a small step in the right direction occurred when the FDA announced that some manufacturers that use certain short-chain PFAS chemicals “for grease-proofing in paper and paperboard for food packaging (for example, as coatings on some fast-food wrappers, to-go boxes, and pizza boxes) have voluntarily agreed to phase-out their sales of these substances for use as food contact substances in the United States”.[92]

Myth #3: PFAS chemicals can be filtered using common filtration systems like a Brita pitcher or other granular activated carbon (GAC) filtration systems. Note: GAC filtration systems are the main water quality purification method currently used.

Truth: Although GAC can be effective for certain PFAS chemicals (mainly long-chain PFAS chemicals), short-chain chemicals do not absorb as well and can get through the filters. Additionally, according to a US EPA researcher named Thomas Speth, the PFAS chemical removal quality depends on several factors such as “the type of carbon used, the depth of the bed of carbon, flow rate of the water, the specific PFAS you need to remove, temperature, and the degree and type of organic matter as well as other contaminants, or constituents, in the water”.[93] Finally, a joint report conducted by the USGS and US EPA suggests that drinking water treatment plants nationwide are not employing the proper techniques to remove PFAS chemicals from drinking water.[94]45 The report found that water prior to treatment contained on average a total PFAS concentration of roughly 21ppt, but that after treatment the drinking water still contained an average total PFAS concentration of 19.5ppt.

Myth #4: It is possible to “get rid of” PFAS chemicals.

Truth: If by “get rid of we mean “remove”, then see myths 1 and 3 above. But, if we mean “break down or destroy permanently, then this is a bit more complicated. Presently, the only way that is believed to successfully “destroy” PFAS chemicals is to burn them at above 1000℃, which is thought to break the chemicals down into their “component elements”, or a bunch of carbons, fluorines, hydrogens, etc. It turns out, though, that this idea is not exactly founded on scientific evidence but rather it is considered theoretically possible. Some scientists have argued that solid evidence must be put forward for this idea to be used as a realistic option to permanently remove PFAS chemicals from contaminated sources in the environment.[95]

Ways To Avoid PFAS Exposure

Now let’s get to the burning question: With the pervasive usage of PFAS chemicals, are there established ways to avoid PFAS chemical exposure in the everyday products we use? Yes!

Water Filtration Systems: As was briefly addressed in Myth #3 above, granular activated carbon filtration systems can sometimes work, but only for a portion of PFAS chemicals and they seem to be quite variable. One study showed that dual-stage filters and reverse osmosis filters that were installed under sinks resulted in “near-complete removal for all PFAS [chemicals] evaluated”.[96] Additionally, you can contact your local, city, or state government to inquire about how to get your water tested. As previously discussed, some cities and states have their own advisory levels for PFAS contamination in drinking water. One study explained that if your local advisory levels differ from the federal recommendations, it is always prudent to err on the side of caution and abide by the stricter guidelines.[97] Another point of interest is that PFAS chemicals should not be the only concern when considering drinking water quality. Other chemicals may be found at altering levels based on your zip code. The Environmental Working Group put together a database that lists the most common contaminants in your zip code’s tap water, at what levels they appear, and which filtration system they recommend.[98] It is important to note that you should also check local or federal guidelines for the contaminants in your drinking water to assess its safety.

Fluorine-Free DWR Products: DWR, or Durable Water Repellent, is a product that has many applications from rain jackets to swim trunks to waders for fishing. This product keeps us dry on the wettest of days and can even keep our clothes from getting stained when coffee or wine is accidentally spilled on them. The issue is that DWR is commonly made using PFAS chemicals because of the strong carbon-fluorine bond previously discussed in this article. The good news is that companies are beginning to call themselves out and change the products they are using. For example, Patagonia has decided to make nearly 90% of its products “PFC-free by Fall 2022”.[99] As a reminder, PFC, or perfluorinated chemicals, is a term that was previously used to describe PFAS chemicals. Fluorine-free DWR products are becoming more popular. It should be noted that even though a product is labeled “eco friendly” and “renewably sourced”, this does not mean that its byproducts or sustained use are toxic-free. That said, fluorine-free DWR products are a step in the right direction.

PFAS-Free Consumption: At Surfrider Foundation, we recently put together an Ocean Friendly Foodware Guide.[100] This guide provides good ocean-friendly alternatives for takeout containers, hot and cold cups, straws, and more, while avoiding single-use plastics as well as products that contain fluorinated chemicals like PFAS. It also helps walk you through the costs and benefits of using ocean-friendly products. We also put together a database of Surfrider Ocean Firendly Restaurtants.[101] Be sure to look at that to scout out your next ocean-friendly meal! Finally, check out the Clean Water article on Surfrider Foundation’s Beachapedia for ways to get involved with other initiatives, campaigns, and programs we have around the important topic of clean water.[102]

Policy Actions and Programs

Currently, PFAS chemicals are legally dealt with and litigated individually. Arguments have been made that the PFAS family should be broken into classes so that they are easier to navigate legally.[103] [104] The idea is that if two chemicals are structurally similar and functionally identical, then they should be grouped. This is because historically when one PFAS chemical is banned from manufacturing and use, the manufacturer simply replaces it with a functionally similar but structurally different-enough PFAS chemical to avoid the legal ramifications; for example, DuPont replaced PFOA with Genx and 3M replaced PFOS with PFBS.[105]63 This has left some baffled by the lack of stringent toxicological requirements around the replacements, which have started showing similar ecotoxicological effects.[106] Considering the controversially murky legal history of PFAS chemicals, what has been done, and, equally important, what is being done?

United States

Federal Government
The US federal government, though not as ambitious as other countries, is certainly beginning to address PFAS chemicals. As of October 2020, there are 101 pieces of legislation listed on the US government’s website that address PFAS chemicals.[107] Of them, only 4 have been passed. Three of those were National Defense Authorization Acts for Fiscal Years 2018-2020 (NDAA). These 4 pieces of legislation detail prohibiting PFAS use in “Meals Ready-to-Eat packaging”, which is a food service used primarily by the US military to feed deployed troops; “Replacement of fluorinated aqueous film-forming foam [AFFF] with fluorine-free fire-fighting agent”; and providing instructions for proper “disposal of materials containing [PFAS chemicals] or AFFF” among other items. In May 2019 Senators Debbie Stabenow (D-MI), Marco Rubio (R-FL), and Gary Peters (D-MI) introduced the PFAS Accountability Act (S. 1372)[108] “to hold federal agencies accountable for addressing contamination for per- and polyfluoroalkyl substances (PFAS) at military bases across the country”.[109] As of November 2020, this bill has yet to be voted on by either the House or the Senate. Other efforts though have not been successful. In June 2019 Senator Tom Carper (D-DE) tried to add an amendment to the National Defense Authorization Act (H.R. 535)[110] that would “designate per- and polyfluoroalkyl substances as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980”. Unfortunately, this amendment was unsuccessful. Finally, several federal agencies are investigating PFAS chemicals to assess the human and environmental health risks that these chemicals pose. In response to their ongoing findings, the agencies are establishing programs and influencing legislative efforts to address the current state of PFAS chemicals.[111] [112]74 [113]

State Governments
In the United States of America, we have two main levels of government: the federal government and state governments. The federal government addresses the country as a whole. State governments can be more critical in their analyses as their main focus population is much smaller and more specific. Because of this, some states have gone further than the federal government with their state laws regarding PFAS chemicals. For an in-depth breakdown of all state laws regarding PFAS chemicals, please visit the Safer States’ report.[114]

US Tribes and Territories
There is not a lot of information on PFAS chemicals for Tribal and Territorial laws. The US federal government is now offering grant money to tribes and territories in hopes to help clean up past PFAS chemical contamination spots. For the fiscal year 2020, the US EPA set aside $13 million to help states, territories, and tribes address toxic chemical-related issues. However, in the announcement they state, “while EPA encourages grantees to consider using funds to address per- and polyfluoroalkyl substances (PFAS), grantees are not required to do so, and may direct the funds to their highest priorities”.[115] Finally, tribal leaders have begun taking legal action against PFAS manufacturers, the US federal government, and others involved in the manufacturing and use of PFAS chemicals near their land.[116]

International

The United States of America is not the only country assessing and addressing the PFAS chemical issue. Several international governments have taken steps regarding PFAS chemicals. Below is a collection of sources that provide the state of PFAS chemical policies from around the world.

Stockholm Convention
Both PFOA and PFOS have been named as chemicals that Stockholm Convention members should avoid and, if possible, replace with alternative chemicals.[117] [118]

Africa
There is very little information about PFAS chemicals in Africa, not to mention policies. A recent 2020 literature review on PFAS chemicals in Africa suggests that “[t]he prevalence of PFASs in the African environment is exacerbated by poor governance, weak legislation, as well as illegal and uncontrolled importation of products (such as carpets and food packaging materials) containing these compounds from the developed world”.[119] They go on to say that African countries need to start looking at these chemicals more closely and taking them more seriously.

Asia
In April 2019, the International Pollutants Elimination Network (IPEN) put together a comprehensive report on PFAS chemical policies for the entire continent of Asia. Read the full report here.[120]

Australia
The Commonwealth of Australia’s Department of Agriculture, Water, and the Environment has listed out the country’s current state of PFAS chemicals on their website.[121]

Canada
In 2012, PFOA and PFOS were listed as toxic substances and prohibited by the Prohibition of Certain Toxic Substances Regulations, 2012.[122] Despite this, the Canadian Environmental Law Agency (CELA) suggests that Health Canada needs to do more. CELA points out that Health Canada’s maximum acceptable contamination values (MAC) for PFOS (600 ng/L) and PFOA (200 ng/L) are too high when compared to the US EPA’s lifetime health advisory levels for PFOS and PFOA, which are both set at 70 ng/L.[123]

Central and South America
Despite PFAS-based chemicals being used heavily throughout these areas, laws regarding them within Latin American countries seem to be absent. Outside countries, such as the US, who use PFAS chemicals in pesticides and other applications in their business within the borders of Latin American countries, rely on their own federally recognized laws. This appears to be the only PFAS chemical regulations or restrictions for use within Latin American countries.[124]

European Union
The European Union has been taking measures to deal with PFAS chemicals. Check out the European Chemicals Agency website for more detailed information.[125]

New Zealand
In 2018, New Zealand’s Ministry for the Environment (MFE) commissioned an extensive literature review to assess the impact of PFAS on ecosystems.[126] This report, along with previous research indicating certain PFAS chemicals’ exposures were associated with adverse human health outcomes, led the New Zealand MFE to keep an updated list regarding PFAS investigations, reports, and findings worldwide.[127] Additionally, the MFE maintains a website listing any cabinet papers and regulatory impact statements regarding PFAS chemicals.[128]

Further Readings

The interest from scientists and residents are encouraging governments worldwide to take a closer look at the PFAS family of chemicals. Despite the subjectively small number of PFAS chemicals to have been studied, the findings suggest a more serious approach should be taken when considering the manufacturing and use of these chemicals. This is due to the vast number of applications PFAS chemicals are currently being used for, not to mention the number of products these chemicals are used in. Their high prevalence has seen them travel the globe. With PFAS chemicals showing up in unintended places like polar bear serum and aquatic food webs, Surfrider Foundation is calling for stronger legislative action and stricter enforcement of PFAS chemicals. For more information on some of the many sectors that produce or use PFAS chemicals, check out the list below.

PFAS Family Background Readings

PFAS Mapping

PFAS In Drinking Water

PFAS In Oil and Gas Industry

PFAS In Food Service Ware

PFAS In Furniture

PFAS In Governmental Agencies

C8 Panel Information: 2005-2013 Review of PFAS Impacts

PFAS Litigation



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