Microplastics can be carriers of not just harmful chemicals but also potential human pathogens. And plastic pollution is no longer confined to the oceans and seas: cities and urban deltas are hot spots of contamination with microplastics, according to a 2015 study conducted by Deltares and the Institute for Environmental Studies of the VU-University of Amsterdam.
Microplastics are found in places including the water in the canals of Amsterdam, the Amstel River, the North Sea Canal and the Lake IJssel often in concentrations that match, or even far exceed, those in seawater. They have been found in freshwater mussels, but also in several species of snail, sponges and wood lice. They come from degraded litter, worn tyres, synthetic marine paints and textiles. So microplastics are closer than you think, and they are getting closer still.
That raises the increasingly pressing question of the human health risks posed by microplastics. Can the pathogens that bond to microplastics also raise new threats to health as they are transported through water? For example in more vulnerable delta areas where sanitation facilities are not so good, where sewage is hardly treated, if at all, and where there is a major risk of infection and infectious diseases because people bathe in polluted rivers.
In the years to come, Deltares will be intensively spotlighting the issue of microplastics and human health on the basis of our expertise in the fields of microbiology, environmental toxicology and transport models. Together with the Institute for Agricultural and Fisheries Research in Belgium we do research into the hygienic aspects of microplastics. This is important because: ‘We know that we are exposed to microplastics; we just don't know yet to what extent they can harm our health,' says Deltares expert and ecotoxicologist Dick Vethaak.
In this project Deltares worked together with the following partner: