Jose Julio Ortega-Calvo has been a researcher at Institute of Natural Resources and Agrobiology of Seville, Spanish National Research Council (IRNAS-CSIC) since 1996, and has worked on the bioavailability and biodegradation of organic pollutants for the last 25 years. After completing his Ph.D. at University of Seville in 1991, he worked on different aspects of microbial ecology during postdoctoral stays at the University of Amsterdam (UvA, The Netherlands) and Cornell University (USA). Dr. Ortega was the President in Europe of the Society for Environmental Toxicology and Chemistry (SETAC Europe) in 2016/2017. He is a member of the Stakeholder Bureau of the European Food Safety Authority (EFSA), member of the External Science Advisory Panel (ESAP) of the Long Range Research Initiative at the European Chemical Industry Council (CEFIC-LRI), and Associate Editor of Science of the Total Environment journal. John Robert Parsons completed his PhD on the biodegradation of chlorinated aromatic compounds at the University of Amsterdam (UvA) under the supervision of Prof. Dr. Otto Hutzinger. He currently works at the Institute for Biodiversity and Ecosystem Dynamics at the same university. His research focuses on the environmental behaviour of organic contaminants and how they interact with natural biogeochemical processes, particularly the fate of organic pollutants or contaminants in the environment and how they interact with organic matter (sorption) and with microbial communities (biodegradation), and the relationships between these interactions (bioavailability).