The minuscule bits of plastic invisibly bobbing around in drinking water do not pose a threat to human health, according to a World Health Organization assessment published yesterday (August 21).

Microplastics are those anywhere in size from 100 nanometers to 5 millimeters wide—though there’s no official definition. According to the WHO report, the plastic particles get into drinking water through run-off and wastewater effluent, and those found in bottled water may have something to do with the bottling process, Reuters reports.

Scientists and consumers have been concerned that chemicals found in plastics or pathogens might make their way into the body via microplastics and cause damage, as The Guardian reports. Yet that fear is not backed by science, according to the report.

“[J]ust because we’re ingesting them doesn’t mean we have a risk to human health,” Bruce Gordon, WHO’s coordinator of water, sanitation, and...

See “Plastic Pollutants Pervade Water and Land

“Based on the limited evidence available, chemicals and microbial pathogens associated with microplastics in drinking water pose a low concern for human health. Although there is insufficient information to draw firm conclusions on the toxicity of nanoparticles, no reliable information suggests it is a concern,” the report states.

The UN has called for more research into microplastics and their potential health effects, The Guardian reports.

Although he agrees that there’s no current cause for alarm, Andrew Mayes, a senior lecturer in chemistry at the University of East Anglia in the UK who didn’t participate in the WHO report, also warns against complacency. “Even if we stop (adding) plastic to the environment right now, microplastics will increase as larger pieces divide into smaller and smaller pieces,” Mayes tells the AP.

Further, we are adding plastic to the environment: Its production has been increasing exponentially and is expected to double again by 2025, according to the report.

As it calls for more research, the WHO does not recommend investing effort in monitoring for microplastics in drinking water because resources would be better spent removing pathogens, a proven risk, The Guardian reports.

Gordon agrees, as he tells the AP, mentioning typhoid and cholera. “These are things that cause immediate illness and can kill a million people,” he says.

The same processes that treat wastewater and drinking water also remove many microplastics, according to a WHO press release, meaning that it is possible to make progress toward both goals—microplastics and pathogen removal—at once.

Ashley P. Taylor is a New York–based freelance reporter. Follow her on Twitter @crenshawseeds and read her work at ashleyptaylor.com.

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