Read the full article by Andrew Turley (Chemical Watch)

“An international group of scientists has outlined – with reference to per- and polyfluoroalkyl substances (PFASs) – a scheme for differentiating chemicals of concern according to the “essentiality” of their uses.

The aim is to improve the way in which regulators phase out chemicals, by helping them to identify uses that should form the basis of exemptions.

The scheme is the work of the Global PFAS Science Panel, a sub-group of academics and regulatory scientists that last year called for changes to regulations in the Zurich Statement. It is based on the ‘essential use’ concept from the Montreal Protocol, which required phase out of ozone-depleting substances.

The protocol defines an essential use as:

  • necessary for health, safety or the functioning of society; and
  • a use for which there are no available technically and economically feasible alternatives.

The scheme, which is described in a paper published in Environmental Science: Processes & Impacts last month, assigns substances to one of three categories:

  • category 1 non-essential, the substance fulfils functions that might be considered ‘nice to have’;
  • category 2 substitutable, it fulfils important functions but viable alternatives exist; and
  • category 3 essential.

When applying the scheme to PFASs, the scientists would assign, for example, their use in cosmetics to category 1 and their use in membranes for the chlor-alkali process to category 3.

‘It is neither practical nor reasonable to ban all uses of PFASs in one step,’ they say.

‘However, if some uses are found not to be essential to health, safety or the functioning of today’s society, they could be eliminated without having to first find functional alternatives providing an adequate function and performance.’

The Stockholm Convention, which aims to control the risks from persistent organic pollutants, includes provisions for exempting some uses. However, the legal text does not include clearly defined criteria for identifying those to which key terms, such as ‘specific exemption’ and ‘acceptable purpose’, should be applied.

The scientists conclude that ‘clear legal guidelines for what constitutes an essential use …  will benefit the Stockholm Convention and other regulatory frameworks.’

Asked whether markets should decide what chemicals are essential through pricing, Ian Cousins, professor of environmental science at Stockholm University and first author for the paper, said: ‘The markets are highly imperfect. Many of the costs of chemicals, such as impacts on human health and the environment, are externalities not reflected in the price of the chemical and borne by society as a whole.’

On the role of consumer behaviour, co-author Zhanyun Wang at ETH Zurich said that industry should be transparent about chemicals in consumer products to facilitate informed decisions. ‘We all have smartphone apps to help us to digest such information. So don’t be afraid that consumers won’t be able to understand.’ “