Prof. Ok maintains a worldwide professional network through his service as a CoEditor-in-Cheif for Critical Reviews in Environmental Science and Technology, and Associate Editor for Environmental Pollution and Bioresource Technology, and as a Member of the Editorial Boards of Chemosphere, Journal of Analytical and Applied Pyrolysis and several other top journals in the field. Prof. Ok is the founding chair and organizer of many internationally leading conferences, such as The 20th International Conference on Heavy Metals in the Environment (ICHMET 2020, Korea) and The 9th International Conference on Geochemistry in the Tropics & Sub-Tropics (GEOTROP 2019, Australia).