Researchers around the world have been able to detect microplastics in numerous drinking water samples, both in bottles and in tap water. The World Health Organization (WHO) has now studied whether and what are the health consequences of microplastics. In fact, the result is more reassuring than one might expect: until now, there has been no detailed evidence that microplastics in drinking water are harmful to health.
However, WHO is not giving the green light, as the study situation is very poor. The organization brought together 50 current studies for the study, but only nine of them specifically address the topic of microplastics in drinking water.
It is also problematic that scientists have not yet established a standard definition for microplastics. The most common category is particles smaller than five millimeters in size. But only the smallest particles are important for the presence in drinking water. These particles have a size of at most one micron, that is, one thousandth of a millimeter. WHO does not assume that particles larger than 150 microns accumulate in the body. The opposite is assumed for the smallest particles. However, there is no evidence for this.
Consequences for health
Furthermore, it is not yet clear how microplastics affect human health. Studies in rats and mice have been conducted so far, but the results cannot be extrapolated to humans, if at all. In studies, animals were exposed to such high concentrations of plastic that, when calculated in humans, they would not have been achievable.
Therefore, WHO currently assumes that microplastics, since they are now present in large quantities, do not pose a health risk. However, further investigation is needed.
drinking water in Germany
Indeed, microplastics were detected in drinking water samples in 2017 in Germany. On average, two and a half particles of microplastic floated in a liter of water from Dortmund and Hamburg. For comparison: other countries had up to 100,000 plastic particles in one liter of water. Wastewater treatment plants in Germany remove most of the plastic from the water. The only problem is that the plastic is then found in the sewage sludge and, for example through fertilization, returns to the environment. It is also possible for microplastics to enter groundwater.