What is one thing that is found everywhere on Earth, even in the most sparsely populated regions of the world? PFAS! What’s PFAS, and how does it get everywhere? Watch to find out!
[Video Description: Barbara, a white woman wearing a long-sleeved black shirt, is standing in front of a gray background.
05:03 – An image of a PFAS compound with a long chain of Carbon and two Fluorine atoms linked to each Carbon and a tail of Oxygen and Hydrogen atoms (on the left).
06:52 – A full screen image: This video is sponsored by RIT/NTID Regional STEM Center. Below is a logo of RIT on the left with National Technical Institute for the Deaf on the right.]
Transcript: What is one thing that is found everywhere on the Earth, even in the most sparsely populated regions of the world, such as Antarctica and the Tibetan plateau? PFAS. Yes, the four letter word is also found inside your blood. PFAS, or per- and polyfluoroalkyl substances, are manufactured chemicals used to make items resistant to grease, water, and stain. They can be found in a variety of items like nonstick cookware, waterproof apparel, takeout containers, firefighting foam, carpets, etc. These chemicals are toxic and are dubbed as ‘forever chemicals’ because they cannot be broken down naturally. Bacteria can’t eat them; fire can’t incinerate them; and water can’t dilute them. A recent global analysis of PFAS levels over the past ten years has found PFAS levels in rainwater often greatly exceed US Environmental Protection Agency (EPA) advisory levels. The contamination is consistent even in remote areas like the Tibetan Plateau, where researchers found some chemicals exceed EPA guidelines by 14-fold. Basically, there is nowhere on Earth where the rain would be safe to drink. What will happen to us if we drink or ingest PFAS? Current studies show a link between forever chemicals and increased risk of certain cancers, increased cholesterol, developmental changes in children, adverse effects during pregnancy on the child, and weakened immune system. There are many efforts underway to combat PFAS proliferation. Filtering PFAS from water has been successful; however, there are a few challenges to disposing of PFAS once it is removed. One commonly used method to try to destroy them has been to incinerate the chemicals at extremely high temperatures, as is done with some other types of hazardous waste. But there’s a danger in doing so because the process will also send PFAS into the air, spreading them anew. Another commonly used method is to bury the chemicals in landfills, but the chemicals will leach out and enter our groundwater. Despair not… There is some good news! New research at Northwestern University found PFAS’s weakness… The secret to PFAS’s indestructibility lies in its chemical bonds. PFAS contains many carbon-fluorine bonds, which are the strongest bonds in organic chemistry. As the most electronegative element in the periodic table, fluorine wants one more electron — and badly. Carbon, on the other hand, is more willing to give up its electrons. When there’s that kind of difference between two atoms — and they are roughly the same size, which carbon and fluorine are — that’s the recipe for a really strong bond. While studying the compounds, the researchers at Northwestern University noticed that PFAS contains a long tail of unyielding carbon-fluorine bonds. But at one end of the molecule, there is a charged group that often contains charged oxygen atoms. The researchers targeted this head group by heating the PFAS in dimethyl sulfoxide (C2H6OS) with sodium hydroxide (NaOH). The process decapitated the head group, leaving behind a reactive tail. That triggered all these reactions, and it started spitting out fluorine atoms from these compounds to form fluoride, which is the safest form of fluorine. Although carbon-fluorine bonds are super strong, that charged head group is the Achilles’ heel. This new technique shows promise of being safer and more energy efficient than previous methods. This new process could break down PFAS after they have been filtered from the water, ultimately preventing the chemical from ending up in a landfill and leaching into the soil. Currently, this new method only works on a few types of PFAS. Still, researchers are hopeful that this is just the beginning of new techniques that can eventually be applied to safer drinking water and a healthier environment.
