Out of the frying pan and into the fire: The fishy tale of perfluorinated compounds.

Photo by waferboard | flickr.com

Photo by waferboard | flickr.com

This article is part of a 6-day series titled "Toxicants in Consumer Products".  The authors, with background knowledge in environmental toxicology, will delve into the most pressing ecotox issues of today.

Found in a wide range of consumer products including Teflon coated cookware, textiles, paints, fire-retardant foams, stain-guard, lubricants, and food packaging, perfluorinated compounds (PFCs) have emerged as a persistent pollutant.  Not only do these compounds contaminate the environment, they also are a concern for human health.

What are PFCs?  

PFCs are a group of synthetic (i.e., man-made) chemicals, which are long carbon-fluoride chains with various functional groups at one end. The structure of these chemicals give them unique attributes, such as stability (resist degrading), water and oil repellency, and reduction of solvent surface tension. It is these attributes which make them useful in a variety of consumer products, but also that make then especially persistent in the environment. Two of the most persistent PFCs, perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), have been found in water, wildlife, and humans all around the world.

How do PFCs get into the environment, and why should I care?

Due to the heavy use of PFCs in consumer products, they have been found in bodies of water, plants, fish, reptiles, and marine mammals worldwide. Once released into the air and water from various products or through their industrial manufacturing, PFCs remain in the environment and accumulate over time. Due to its persistence and bioaccumulation, PFOS is even considered a Persistent Organic Pollutant (POP) under the Stockholm Convention. PFC concentrations vary greatly depending on the location and type of PFC.  

A spoonful of PFCs  

While PFCs are a concern to the environment, they also pose a concern to human health. Although humans can be exposed to PFCs through drinking water and contaminated air, the most common route of exposure is through food. So how do PFCs get from your Teflon-coated pan or stain repellent, and onto your dinner plate? Firstly, PFCs are released into the water supply or the atmosphere, and then enter plants, organisms, and small animals at the bottom of the food chain. These are then either directly eaten by humans through the process of bioaccumulation, the contaminated plants and organisms are eaten by larger animals and continue to increase in concentration within the food web. Other routes of exposure for humans, although quite minimal, include PFC release during food preparation, and residuals in food packaging, such as microwave popcorn bags. Even though PFCs are consumed in food, research to date has shown that daily dietary intakes are far below the tolerable daily intake levels (150 ng/kg body weight for PFOS, and 1500 ng/kg body weight for PFOA).

Once in the body, PFCs can have a variety of toxic effects, including increased risk of cancer, liver disease, and immune and endocrine disorders, and neonatal mortality (death of a fetus before birth). However, most of the studies investigating potential health effects from PFC exposure are from animal studies, and there is limited epidemiological data for humans at this time.  Although these chemicals are persistent and toxic, the average dietary intakes of PFCs is typically 10,000 times less than the doses used in animal studies that cause adverse effects. As the saying goes, the dose makes the poison, so although these chemicals have the potential to cause serious harm, the levels found within humans are likely not causing serious adverse effects.

The good news?

Although PFCs have been around for over 50 years with little regulation, that has changed in recent years. Canada was actually the first country to implement limitations on PFCs, by temporarily banning four fluorinated polymers in 2004, and permanently banning them in 2006.  In both the United States and the European Union, similar restrictions have now been put in place. Starting in 2000, the production of PFCs has also been significantly reduced, mainly due to agreements between companies and government bodies. Although this is promising, not all countries have had a similar regulatory reaction to PFCs, such as China, where PFOS production has increased from 2003-2006. Regardless, due to the persistence of PFCs in the environment, and their widespread use for many years, PFCs will likely remain both an environmental and human health concern for many years to come.