Dr. Leonard Osté is the chair of the working group on Zero Pollution of Water Europe. He has a wide experience in soil, sediment, and surface water quality. He has done a lot of work in developing legislation and guidelines. He was involved in the development of Dutch standards for reuse of sediment and he was a member of the drafting group for an EU guidance on bioavailability of metals. In recent years, he has focused more on contaminants of emerging concern with a specific interest in the occurrence of PFAS in different compartments. He was involved in prioritization studies on a national and European level, trying to select the most relevant compounds out of thousands of chemicals. He is also a member of the NORMAN working group on prioritisation of emerging compounds.