Hydrolysis is an abiotic degradation process that influences the fate of many water-soluble substances in the environment. The ability of chemicals to undergo hydrolysis is currently tested in purified lab water in accordance with ⁠OECD⁠ guideline 111. It has been suggested that the addition of particles such as sediment or microplastic fibers i.e. may result in a change in the rate of hydrolysis. The project showed that adding commonly occurring particles in aquatic environments can lead to a reduced hydrolysis rate of organic substances, probably especially for sorbing cationic compounds. However, this effect is small compared to the influences known to occur for changes of pH or temperature.