24 aug 2019
The World Health Organization (WHO) has called for a further assessment of microplastics in the environment and their potential impacts on human health, following the release of an analysis of current research related to microplastics in drinking water.
According to the analysis, 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.
The potential hazards associated with microplastics come in three forms: physical particles, chemicals and microbial pathogens as part of biofilms. Based on the limited evidence available, chemicals and biofilms 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 related to the physical hazard of plastic particles, particularly for the nano size particles, no reliable information suggests it is a concern.
WHO recommends drinking water suppliers and regulators prioritize removing microbial pathogens and chemicals that are known risks to human health, such as those causing deadly diarrhoeal diseases. This has a double advantage: wastewater and drinking water treatment systems that treat fecal content and chemicals are also effective in removing microplastics.
Wastewater treatment can remove more than 90 percent of microplastics from wastewater, with the highest removal coming from tertiary treatment such as filtration. Conventional drinking water treatment can remove particles smaller than a micrometer.
A significant proportion of the global population currently does not benefit from adequate water and sewage treatment. By addressing the problem of human exposure to fecally contaminated water, communities can simultaneously address the concern related to microplastics.