Abstract

Microplastics are small plastic particles less than five millimetres across. More and more microplastics are ending up in the environment. They are everywhere: not just in water and air but also in soil, including in urban areas, on farms and in nature reserves. There are indications that microplastics pose a risk to the health of humans, plants, animals and soil life. An increasing number of publications on microplastics in the soil have featured in the scientific literature recently. And yet there is still a lack of clarity on whether or not there are potential risks.

This is why the National Institute for Public Health and the Environment (RIVM) deems further clarification important. Consequently, it has summarised the available knowledge for policymakers and risk assessors. This information proves to be fragmentary, incomplete and sometimes even contradictory, as a result of which it cannot (or cannot yet) be used to arrive at a reliable risk assessment. For example, there are no measurements available of microplastics in Dutch soils. This is largely down to the fact that no reliable, practical, standard techniques exist to analyse microplastics in the soil. These need to be developed.

More knowledge will be required to reliably gauge the environmental risks presented by microplastics. RIVM recommends better charting of the sources from which microplastics are released and how they are dispersed in the environment. In addition, a greater degree of insight is needed into the rate at which various types of plastic break down as well as the rate at which microplastics break down into harmless compounds. This is necessary for the purposes of gauging exposure. To support efforts to this end, the RIVM has created a ‘conceptual model’.

Another recommendation is to simultaneously assess the risks posed to the soil by various types of microplastic. The substance risk assessment frameworks currently in place are unsuitable for this as microplastics occur in various forms and compositions. Finally, a list has been drawn up of what is known about measures geared towards reducing the release of microplastics. Examples include a ban on free plastic bags and deposits on PET bottles.