‘Forever chemicals’ that are contaminating rainwater globally

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 PFAs?

• According to the US Centre for Disease Control and Prevention (CDC), 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. 
• 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 kind of harm PFAs causes?

• The United States Environmental Protection Agency (EPA) lists a variety of health risks that 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. 
• The 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?

• 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.
• Recently, Science reported a cheaper method. 
  • 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.