Among many of the artificial substances that have been designed and developed in laboratories, the Per and Polyfluoroalkyl Substances (PFASs) are of much concern and interest to researchers. These substances don’t get easily destroyed under normal environmental conditions. PFASs get accumulated in soil or water and also in the human body. Moreover, they can also pose a threat to human health. This class of substances are used in non-stick cookware, firefighting foams, waterproof clothes and also among oil repellant clothes. A study conducted in 2015 and published in the journal named International Journal of Environment Research and Public Health found that PFASs were found in the blood of 97% of the Americans who participated in the study. PFASs are linked to conditions such as thyroid disease, some cancers and also high cholesterol.
The much durable substances acting as a pollutant and a potential health hazard were originally designed to be stable and that is their characteristic. But, when they get into the environment, they become hazardous.
The other side of the story is that the PFASs can also be removed from the water. However, doing that has proven challenging. If the PFASs are buried in landfills, they can percolate into the surrounding environment and thus might lead to the contamination of soil and groundwater. Moreover, disposing of the PFASs requires expensive and harsh treatments—high pressure and temperature above 1000 degrees Celsius. Again, previous reports showed that incineration can also spread into the environment.
New research has focused on all these loopholes in the previous ways of disposing of these substances. Brittany Trang, an environmental chemist at Northwestern University, Illinois, USA, and a co-author of the study commented,“There’s a need for a method to get rid of PFASs in a way that does not continue to pollute.”
The new study has been published in Science on August 18 and claimed to have developed a method where the disposal can be done using inexpensive reagents and requires a temperature as low as about 100 degrees Celsius.
Trang and her colleagues showed that PFASs can be degraded using DMSO, which is a very common solvent used in cleaners and soaps. Their method using DMSO could break the PFASs into harmless simple products. The team showed that with the newly developed method, they could degrade 10 substances that belong to the PFA class. This includes PFOA, which is a chemical banned in most countries along with one of its common replacements.
Shira Joudan, an environmental chemist at York University, Canada, commented on the new method saying, “Computational analyses suggested that this class of PFASs falls apart two or three carbons at a time rather than one carbon at a time, as generally assumed. Understanding the mechanisms through which these pollutants break down could inform approaches to solve the forever-chemicals problem.” Joudan was not involved in the study. “This is the first time I’ve seen a degradation mechanism where I thought, ‘this could actually make a difference,” Joudan commented further.
Scientists have identified some 12,000 PFASs so far and the new method works well on PFOA and some other closely related chemicals. However, the caveat is that this method does not show applicability to another popular class of PFASs which is known as Perfluorooctane Sulfonic Acid (PFOS). Notably, PFOS is potentially toxic and is not used in some countries. On the other hand, the existing methods can degrade both PFOA and PFOS.
Ian Ross leads consulting on PFASs of Tetra Tech, which is a company based in California. Ross raised apprehensions about the DMSO method and said that the approach may not be practical in real-life. “It’s going to cost you a fortune if you’re going to buy bulk quantities of DMSO and then dispose of the DMSO — you can’t put it down a sewer,” Ross said. Other experts believe that the new approach can lead to the development of newer methods in future for degrading the PFASs.