Do policymakers and scientists have different understandings of "risk"? How can scientific uncertainty be pinned down and quantified? When experts disagree about the evidence, is there anything useful that the policymaker can take away from that disagreement?

Bart Koelmans discusses these questions with Toby Wardman of SAPEA. We also discuss the strength of the evidence for harm from microplastics, the limits of the natural sciences, what numerical value of probability is implied by the word "probably", and how English speakers should try to pronounce the word "Wageningen".

Bart is a professor in Aquatic Ecology and Water Quality at Wageningen University and at Wageningen Marine Research. His main research is on the risks and impacts of microplastic pollution, on which topic he has chaired science advice groups for the UN and European Commission as well as national governments and other policymakers.

As always, the opinions expressed in this episode are those of the speakers and not necessarily those of SAPEA or the European Commission.

• WHO report on microplastics in drinking water: https://www.who.int/water_sanitation_health/publications/microplastics-in-drinking-water/en/