From UPSC perspective, the following things are important :
Prelims level : PFA, Forever Chemicals
Mains level : Residual chemicals and the pollution caused
A recent study published in Environment Science and Technology has found that rainwater from many places across the globe is contaminated with “per- and polyfluoroalkyl substances,” (PFAs) also called “forever chemicals”.
What are PFAs?
- PFAs are man-made chemicals used to make non-stick cookware, water-repellent clothing, stain-resistant fabrics, cosmetics, fire-fighting forms and many other products that resist grease, water and oil.
- They refer to a group of over 3,000 widely used human-made chemicals linked to cancer and other health risks.
- They have tendency to stick around in the atmosphere, rainwater and soil for long periods of time.
- 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.
What harm do PFAs cause?
- A variety of health risks are attributed to PFA exposure, including 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.
How can these chemicals be removed from rainwater?
- 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 has 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.
- A cheaper method is under trial.
- The researchers first placed a PFA compound in a solvent called DMSO (dimethyl sulfoxide).
- They then mixed it with sodium hydroxide (lye) in water.
- They found that when this mixture was heated up to boiling temperature, the PFA compound began to degrade.
- However, this method doesn’t work for all PFAs and only works for certain PFA subsets.