The Government has been warned it must act on so-called “forever chemicals” leaking into the UK environment amid concerns over the concentration levels in drinking water.

The Royal Society of Chemistry (RSC) is calling on the UK Government to overhaul its drinking water standards to tackle the risk of PFAS, which have been linked to health issues such as liver damage, testicular cancer and developmental defects in unborn children.

PFAS – more commonly known as forever chemicals because they do not break down – enter water courses through industrial discharges and household waste.

Under current regulations, UK drinking water can have up to 100 nanograms of PFAS per litre before a water company has to take action.

But the RSC is calling on the Government to reduce this cap to 10 nanograms per litre for 47 types of PFAS and 100 nanograms for the overall summed concentration of all PFAS.

The organisation said the UK’s thresholds for PFAS in drinking water are currently far more lenient than those in other leading economies.

It comes after a new analysis of data from the Forever Pollution Project showed that 35% and 37% of English and Welsh water courses that were tested contain levels of PFOS and PFOA that would be considered a medium or high risk if found in drinking water.

The RSC is arguing for a “precautionary approach” after it calculated that a safe level per litre per day in drinking water could be 22 nanograms of a combination of four chemicals – PFOS, PFOA, PFHXS and PFNA.

The UK Committee on Toxicity, which advises the Government, has reservations about the evidence base behind these calculations and is undertaking its own evaluation of safe levels.

However, the RSC said this could be an expensive and lengthy process.

David Megson, a senior environmental chemist at Manchester Metropolitan University, said: “As we start to understand more, we’re finding that more and more PFAS are displaying these adverse health effects.

“So there’s thousands of these things in the environment, they’re not going away anytime soon and they are causing damage to us so we need to find a way to manage them effectively.”

Water companies are required to test for 47 different types of PFAS in drinking water, sending samples to the Government’s Drinking Water Inspectorate (DWI).

The RSC said this means water firms are adhering to current standards but there is no requirement to publish the data so it is impossible to know the level of PFAS in drinking water within the existing limits.

The RSC is also calling for ministers to ensure that the many hundreds of types of forever chemicals are reported and captured in a national inventory.

Other measures recommended by the organisation include enforcing stricter regulatory limits on allowable levels of PFAS in industrial discharges and developing plans for a national chemicals regulator to provide better strategic co-ordination.

A Department for Environment, Food and Rural Affairs spokesperson said: “Drinking water standards in England are of an exceptionally high standard and are among the best in the world.

“Water companies are required to carry out regular risk assessments and sampling for any substance – including PFAS – that they believe may cause the water supply to pose a risk to human health.

“Work is continuing across Government to help us assess levels of PFAS occurring in the environment, their sources and potential risks to inform future policy and regulatory approaches.”