One of the questions I鈥檝e been asked recently with increasing frequency is how to avoid exposure to those 鈥渇orever chemicals鈥� that we are being warned about in numerous newspaper articles, books, and social media sites. These are the 鈥減erfluoroalkyl substances,鈥� commonly referred to by the acronym PFAS, pronounced as 鈥減eefas,鈥� that constitute a family of some 9000 compounds. Many are used in a wide array of consumer items on account of their resistance to both water and fats as well as for their lubricant properties. They are found in stain-resistant fabrics, food packaging, water-resistant cosmetics, non-stick cookware, rain gear, ski wax, tent materials, windshield wipers, adhesives, paper products, paints, gaskets, hoses, floor polishes, food processing machinery, construction materials, fire-fighting foams and literally hundreds of other products.
The desirable properties of these perfluoroalkyl substances are a function of the fluorine atoms bonded to the network of carbon atoms that make up the basic PFAS structure. The carbon-fluorine bond is extremely strong and is not easily broken by microbes in the environment meaning that these substances are not biodegradable thereby accounting for their 鈥渇orever鈥� moniker. Their environmental persistence wouldn鈥檛 really be a problem if these chemicals had no biological activity. But it seems that they may very well have some adverse effects which brings up the question of how to avoid them. The simple answer is that total avoidance is not possible but there may be ways to reduce exposure.
PFAS have been commercially used since the 1940s and their resistance to biodegradation has made them ubiquitous in the environment, commonly showing up in our food and water. As a result, these compounds can be detected in virtually everyone鈥檚 blood, and just as they resist breakdown in the environment, they also stand up to the body鈥檚 detoxicating enzymes. But how great a worry is this?
There is no shortage of studies. Hundreds of laboratory experiments, animal trials, and human epidemiological investigations have been published. Many suggest that these 鈥渇orever鈥� substances can cause biological mischief, but the evidence is certainly not ironclad and one can pick and choose among the studies to either convict or absolve them of crimes against humanity. Reading through the numerous publications, one is left with the impression that while some smoke can be observed, it is not likely to come from a raging inferno.
Several concerns have been raised. The one that has received the most publicity is 鈥渆ndocrine disruption,鈥� meaning that some PFAS may have hormone-like effects. Exposure would then be of particular concern during pregnancy and infancy. Indeed, an association has been found between prenatal exposure and later obesity in children. Thyroid hormone abnormalities may also be associated with PFAS exposure. Since these chemicals accumulate in the liver, a number of studies have investigated liver function with respect to PFAS concentration. Some studies have linked elevated liver enzymes, a possible sign of liver malfunction, with PFAS, and there also seems to be an association with non-alcoholic fatty liver disease. Studies have also examined a potential link with cancer and found an association between exposure via drinking water and the development of testicular and kidney cancers. As always, it is important to remember that associations cannot prove a cause-and-effect relationship and that there are also studies that have found no connection between PFAS and any abnormality.
While consumers can reduce exposure by not buying microwave popcorn, water-resistant cosmetics, stain-free garments, fluorinated ski wax, or French fries in oil-resistant cartons, the impact is likely to be small. Industry has to take this bull by the horns and find alternative materials, or at least determine exactly which PFAS have the smallest environmental impact. This is being done. The most troublesome compound, perfluorooctanoic acid, PFOA, has already been phased out. It was widely used in the manufacture of Teflon cookware, although it did not end up in the finished product. Whether the replacement processing chemicals, which are also fluorinated, are better, isn鈥檛 clear.
An oft-asked question is whether consumers should stay away from Teflon cookware because of this concern. There is no reason to worry about the finished product because non-stick pots and pans do not release PFAS in any significant amount. A more valid concern is release of these chemicals into the environment during manufacture. So, if there is less demand for cookware made with perfluoroalkyl substances, then production will decrease, and fewer PFAS will be released into the environment. Ceramic coatings and anodized aluminum are suitable alternatives.
Bottom line: Perfluoroalkyl substances have numerous important applications and their total elimination is out of the question. Alternatives for some applications, such as in food packaging, can be found and stain-free fabrics and fluorinated ski wax are not necessities of life. Given the lack of consensus in studies about PFAS, and the fact that we are exposed to thousands of both naturally occurring and synthetic compounds every day with varying degrees of toxicity, it is not possible to come to a conclusion as to the impact of these 鈥渇orever鈥� chemicals.
