Researchers from Swansea University have warned that disposable face masks could be releasing chemical pollutants and nano-plastics into the environment.
Scientists said there needed to be better regulation and more research carried out.
The Swansea University team found heavy metals and plastic fibers were released when throw-away masks were submerged in water.
The researchers said the public health impact needed more investigation.
“Before the pandemic, we were looking at reducing the use of plastic straws, reducing packaging, but now we are looking at hundreds and thousands of these masks being disposed,” said the project leader, Dr Sarper Sarp, of the university’s College of Engineering.
“We need to sort our priorities – first of all we need to get over the pandemic and protect each other and the public health. Then, in the meantime, we need to take steps to protect the environment.”
But as they tested more and more masks, they uncovered more chemicals.
The pollutants were often linked to dyes used in producing the masks, mostly made in southern Asia, and China in particular.
The team found traces of lead, antimony and cadmium – all heavy metals which can be toxic in low doses.
They said the levels found were in the range of parts per million or parts per billion.
“On an environmental scale with the amount of production of these things – it all accumulates,” warned Dr Geraint Sullivan, technology transfer fellow at the university.