Registration procedures for substances of high concern: fate, behaviour, degradation and potential accumulation of potentially persistent, bioaccumulative and toxic (PBT) substances in aquatic meoscosms

Persistent, bioaccumulative and toxic (PBT) compounds deserve specific attention when considering the hazard, which these substances might cause to the environment. These circumstances are taken into account by the European Union in the REACH regulation. For example, for persistent compounds it is difficult to predict long-term effects by established risk assessment procedures, since low degradation rates and potential accumulation hamper exposure assessment.

The aim of the project was to scrutinise, if data on abiotic degradation (e.g. hydrolysis, photolysis) are sufficient to dispel an initial suspicion of persistence for a compound. For three selected model substances with assumed persistent and adsorptive properties, degradation data from various types of studies including water-sediment systems, aquatic indoor mesocosms, and artificial ponds were generated. The comparison of all data for each test compound elucidated the pros and cons of complex and near to nature test systems when assessing the persistence of a compound.