What are 'Forever chemicals'?

In news–New study has found that rainwater from many places across the globe is contaminated with “per- and polyfluoroalkyl substances,” (PFAs), which are called “forever chemicals” because of their tendency to stick around in the atmosphere, rainwater and soil for long periods of time.

What are PFAs/forever chemicals?

PFAs are man-made chemicals used to make nonstick cookware, water-repellent clothing, stain-resistant fabrics, cosmetics, firefighting forms and many other products that resist grease, water and oil.
PFAs can migrate to the soil, water and air during their production and use.
Since most PFAs do not break down, they remain in the environment for long periods of time.
Some of these PFAs can build up in people and animals if they are repeatedly exposed to the chemicals.
Health risks that are attributed to PFA exposure are decreased fertility, developmental effects in children, interference with body hormones, increased cholesterol levels and increased risk of some cancers.
Recent research has also revealed that long-term low-level exposure to certain PFAs can make it difficult for humans to build antibodies after being vaccinated against various diseases.

Destroying PFAS-

While there is no known method that can extract and remove PFAs from the atmosphere itself, there are many effective, albeit expensive, methods to remove them from rainwater that have been collected through various rainwater harvesting methods.
One way to do this would be to use a filtration system with activated carbon. The activated carbon will need to be removed and replaced regularly. Also, the old contaminated material must be destroyed.
Current methods to destroy PFAS require harsh treatments, such as incineration at extremely high temperatures or irradiating them with ultrasonic waves.
And incineration isn’t always foolproof, with one New York plant found to still be releasing some of the compounds into the air through smoke.
PFAS’ indestructability comes from their carbon-flouride bonds, one of the strongest types of bonds in organic chemistry.
Fluorine is the most electronegative element and wants to gain electrons, while carbon is keen to share them.
PFAS molecules contain long chains of these bonds, but the US research team was able to identify a glaring weakness common to a certain class of PFAS.
At one end of the molecule, there is a group of charged oxygen atoms which can be targeted using a common solvent and reagent at mild temperatures of 80-120 degrees Celsius, decapitating the head group and leaving behind a reactive tail.
Once that happens, that provides access to previously unrecognized pathways that cause the entire molecule to fall apart in a cascade of complex reactions.
A second part of the study involved using powerful computational methods to map out the quantum mechanics behind the chemical reactions the team performed to destroy the molecules.