C4 vs C6 vs C8: What are these PFAS chemicals and how are these different?
It’s hard enough to figure out how to avoid PFAS chemicals but the heck are C8, C6 and C4?
PFAS, which stands for per-and polyfluoroalkyl substances, are over 6 thousand manmade chemicals made of carbon chains (typically 2 to 16 carbon atoms in length) bonded to fluorine (F) atoms
C8 refer to long chained highly fluorinated chemicals … the number 8 means there are 8 carbons in the “chain” making them some of the “strongest’ and longest - molecularly- of the PFAS family. These chains are what makes these chemicals “forever chemicals” they are so strongly held together that they do not break down easily and thus live inside of us and in the environment for many many years- sometimes over 20 years without breaking down.
Examples of C8 PFAS include: PFOA, PFOS, chemicals used in Teflon which were used for decades to give water-repellant, stain-resistant, and non-stick properties … and some of which are still used.
KNOWN health effects of C8 PFAS
Exposure to PFOA has been linked to kidney and testicular cancer, elevated cholesterol, decreased fertility, thyroid problems and changes in hormone functioning in adults as well as adverse developmental effects and decreased immune response in children1
Due to known hazardous effects and their duration in nature and in our bodies many C8 PFAS have been phased out and replaced by shorter chained fluorinated chemicals…. companies assume that because these ‘newer’ shorter chained PFAS in theory break down faster they must be “better” and “safer”. Many companies, thus, have begun to substitute the longer chained PFAS with the shorter chained ones without looking at safety studies …..another case of regrettable SUBSTITUTION
Let’s take a look at these shorter chained PFAS that are growing in popularity….
What does it mean to be shorter chained?
C6 : considered a shorter chain because they have 6 carbon atoms instead of 8
C4: considered even shorter chained because they have 4 carbon atoms instead of 8
Industry groups will want you to believe that because they are shorter chained they break down quicker and so are “better for the environment. They claim that there are no studies showing ill effects (this is not true but there are not many because they are newer and have not been used for very long) on your health- and so are a better environment
HEALTH EFFECTS of short C6 and C4 PFAS
More recent research is showing that shorter chained PFAS can be just as harmful to our health- and even the planet- as longer chained ones.
16 reports to the EPA filed by DuPont between 2006 and 2013, experimental animals exposed to a commonly used short-chain alternative had increases in several types of cancer and changes to the liver and immune system. These adverse health effects are similar to those from exposure to the old long-chain compounds.
Another study found similarities in the way that short-chain and long-chain compounds adversely impact hormonal systems.
study found that concentrations of short-chain fluorinated chemicals were higher than long-chain chemicals in human kidney, lung, liver, and brain9.
the Danish Environmental Protection Agency10, “the high presence of short-chain [fluorinated chemicals] in human tissue... is worrying.”
To prevent such “regrettable substitutions”, the entire class of highly fluorinated chemicals should be avoided…this means ALL PFAS, regardless of chain length…. but in the meantime how do we make sure we aren’t buying a product that contains ANY PFAS chemicals?
This is hard. Companies don’t always openly share information on what they are using to achieve stain/water repellency . Further complicating things for consumers is the fact that many customer service reps have no idea that C4 based repellants are indeed PFAS based. I cannot tell you how often I get told “no we do not use any PFAS based DWR (durable water repellents) we use a safer C4 based repellent.”
Bottom line: Consumers need to specifically ask about ALL PFAS chemicals- specifically mention C4, C6, C8 when asking companies what they are using in their products.
This is what you can ask:
ie: “Specifically, how does your product achieve water/stain/grease resistance? Does it contain any PFAS based treatment ie C4, C6 or C8?”
The more we ask the more companies will realize this is something that we care about …. PFAS free water/stain repellent technology exists so hopefully by pressuring companies to get rid of PFAS based tech they will look to find truly greener solutions
For more information on PFAS free clothing read PFC/PFAS Free Winter Gear for Kids and Parents
studies
Rosenmai, A. K., et al. Andrology 4.4 (2016): 662-672.
Blum, A., et al. Environmental Health Perspectives 123.5 (2015): A107-A111. 9. Perez, F., et al. Environment International 59 (2013): 354-362. 10. Danish Ministry of the Environment. “Short-chain Polyfluoroalkyl Substances (PFAS). A literature review of information on human health effects and environmental fate and effect aspects of short-chain PFAS.” http://www2.mst.dk/Udgiv/publications/2015/05/978-87-93352-15-5.pdf. Accessed Oct. 17, 2016.
https://enveurope.springeropen.com/articles/10.1186/s12302-018-0134-4