What are per- and polyfluoroalkyl substances?

Context

  • A recent 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 per- and polyfluoroalkyl substances (PFAs)?

  • 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.
  • can migrate to the soil, water and air during their production and use.

    What are per- and polyfluoroalkyl substances?
    Photo Credit: Great Lakes Now
  • Since most PFAs do not break down, they remain in the environment for long periods of time.
  • Some of these can build up in people and animals if they are repeatedly exposed to the chemicals.

What harm do PFAs cause?

  • decreased fertility, developmental effects in children, interference with body hormones, increased cholesterol levels and increased risk of some cancers.
  • long-term low-level exposure to certain PFAs can make it difficult for humans to build antibodies after being vaccinated against various diseases.

Do we need to be worried about PFAs in the rainwater in India?

  • While the recently published research article did not include studies of samples collected in India, the nature of PFAs and the wide geographical breadth of samples and the nature of PFAs means that the results can be extrapolated to India.

How can these chemicals be removed from rainwater?

  • 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 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.
  • 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.

Source: IE


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