Pressure is building on UK ministers to tighten regulations on PFAS “forever chemicals” as research shows vast numbers of people are drinking water with levels that would be banned in the US. On Tuesday, US president Joe Biden announced plans to drive down acceptable limits in drinking water to four nanograms per litre (4ng/l) for two types of per- and polyfluoroalkyl substances (PFOS and PFOA), and announced proposals to regulate four more – PFNA, PFHxS, PFBS and GenX Chemicals – as a mixture. In England and Wales, the Drinking Water Inspectorate’s (DWI) guidelines allow levels of PFOS and PFOA in drinking water 25 times higher, at up to 100ng/l, and until 2021 the limit was 5,000ng/l for PFOA and 1,000ng/l for PFOS. “I think the Americans have this absolutely right and we are out of step,” said Baroness Bakewell, the environment spokesperson for the Liberal Democrats in the House of Lords. “It seems a nonsense that we are determined to poison the population. The government thinks it’s at the forefront of everything, but … this isn’t the case and the government isn’t willing to move forward on the environment.” Former Green party leader Caroline Lucas agreed. “A cocktail of toxic persistent chemicals is polluting our rivers and seas, poisoning our water supply and posing a severe threat to human health, marine and animal life. Yet the UK’s chemical pollution limits are shamefully lagging behind international standards. The government urgently needs to get a grip on this chemical crisis and adopt far tougher regulations now.” PFAS is a group of around 10,000 substances used in a huge number of consumer products and industrial processes for their non-stick properties. They are widespread in the environment and are known as “forever chemicals” because they do not break down in the environment, can build up in the body and some may be toxic. “Communities across [the US] have suffered far too long from the ever-present threat of PFAS pollution. That’s why President Biden launched a whole-of-government approach to aggressively confront these harmful chemicals, and EPA is leading the way forward,” said US Environmental Protection Agency (EPA) administrator Michael S Regan. The new limit “has the potential to prevent tens of thousands of PFAS-related illnesses and marks a major step toward safeguarding all our communities from these dangerous contaminants,” Regan added. Data from water companies and the Environment Agency, analysed by the Guardian and Watershed Investigations, shows that about 1,900 samples of drinking water sources, taken from across the country, contain PFOS or PFOA above the proposed US limit of 4ng/l. The total number is likely to be higher because many samples are reported in bands such as “less than 10ng/l”. “Some of the collected data for detection limits of PFOS and PFOA are significantly greater than the regulatory detection limit set by the US EPA,” according to Dr Cecilia MacLeod, programme leader for wastewater and environmental engineering at the University of Greenwich. “Taking into consideration EPA’s findings with regards to these PFAS compounds on human health, is the UK DWI approach fit for purpose?” Tony Fletcher, epidemiologist at the London School of Hygiene and Tropical Medicine who studies health effects of PFAS, said the US proposals “reflect the welcome trend to stricter regulation. Many regulators in US states and Europe have been setting limits stricter than the old limit of 100ng/l currently in place in Britain. “Data have recently been collected across Britain on PFAS exposures in all drinking water supplies. With that in hand, plus limits such as the EPA ones, I would expect the UK should follow suit and reduce permitted levels for these two, but we also need limits across the large family of PFAS as new compounds keep appearing.” Green party peer Natalie Bennett said the government “claims to follow the ‘precautionary principle’, and we hear an empty boast of being “world-leading” on environmental standards regularly, yet it is patently obvious this is not the reality. “These forever chemicals are a fast-growing area of concern for human and environmental health, linked to decreased fertility, increased cholesterol levels and developmental problems in children. The US is reacting with a major tightening of standards. The UK should follow.” According to Stephanie Metzger, adviser at the Royal Society of Chemistry, the “new US rules give an indication that the UK should be reviewing its current PFAS in drinking water guidelines to ensure that they are in line with the most up to date science”. A spokesperson for the Department of Environment, Food and Rural Affairs said: “UK drinking water standards are among the best in the world and water companies are required to carry out regular risk assessments and sampling for PFAS to ensure the drinking water supply remains safe. Since the 2000s we have increased the monitoring of PFAS and taken actions to support banning or highly restricting specific PFAS both domestically and internationally. We pay close attention to international policy developments – including the EPA’s proposals around PFAS in drinking water – and continue to work at pace across government to assess the levels of PFAS occurring in the environment. In the spring we will publish analysis which will examine the risks and make recommendations to inform future PFAS policy.” Water UK did not respond to requests for comment.