Microplastics found in drinking water do not appear to pose a health risk at current levels, says the first-ever report done by the World Health Organisation on the issue.
The United Nations body found that all larger plastic particles, and most of the smaller ones, simply pass through the body without being absorbed at all.
“Based on the limited information we have, microplastics in drinking water don’t appear to pose a health risk at current levels. But we need to find out more. We also need to stop the rise in plastic pollution worldwide,” said Dr Maria Neira, WHO director for Department of Public Health, Environment and Social Determinants of Health.
Microplastics, defined as small (less than 5mm in length) pieces of plastic debris, have been found in rivers, lakes, drinking water supplies and bottled water.
According to the analysis, which summarises the latest knowledge on microplastics in drinking water, microplastics larger than 150 micrometers are not likely to be absorbed in the human body and uptake of smaller particles is expected to be limited.
Absorption and distribution of very small microplastic particles including in the nano-size range may, however, be higher, although the data is extremely limited.
She said waste water treatment can remove more than 90 per cent of microplastics, with the highest removal coming from tertiary treatment such as filtration.
“Conventional drinking water treatment can remove particles smaller than a micrometre. A significant proportion of the global population currently does not benefit from adequate water and sewage treatment,” said the director.
However, the findings called for further assessment of microplastics in the environment and their potential impact on human health, following the release of an analysis of current research related to microplastics in drinking water.
WHO also called for a reduction in plastic pollution to benefit the environment and reduce human exposure including developing standard methods for measuring microplastic particles in water.
“We urgently need to know more about the health impact of microplastics because they are everywhere including in our drinking water. More studies on the sources and occurrence of microplastics in freshwater; and the efficacy of different treatment processes is also needed,” she said.
WHO last year began a review into the potential risks of plastic in drinking water after a new analysis of some of the world’s most popular bottled water brands found that more than 90 per cent of water contained tiny pieces of plastic.
In the new study, analysis of 259 bottles from 19 locations in nine countries across 11 different brands found an average of 325 plastic particles for every litre of water being sold.
In one bottle of Nestlé Pure Life, concentrations were as high as 10,000 plastic pieces per litre of water. Of the 259 bottles tested, only 17 were free of plastics.
The scientists wrote they had “found roughly twice as many plastic particles within bottled water” compared with their previous study of tap water,
WHO recommends drinking-water suppliers and regulators prioritise removing microbial pathogens and chemicals that are known risks to human health, such as those causing deadly diarrheal diseases.
“This has a double advantage: waste water and drinking water treatment systems that treat faecal content and chemicals are also effective in removing microplastics,” said the study.