Towards rationally designed hazard, risk and persistency assessment: Putting the “bio” back into biodegradability tests

Regulatory emphasis has recently shifted to identifying and prioritising chemicals that are persistent, liable to bioaccumulate and are toxic (e.g. REACH). Chemicals with these properties have previously been shown to be those most harmful to human health and the environment. Biodegradation is one of the most important fate processes that determines persistence, i.e. the rate a chemical degrades in the environment. The ability to estimate or predict biodegradation is critical in determining eventual environmental concentrations, likely exposure and ultimately the risk of long-term adverse effects of chemical substances on biota, including humans. Information on the degradability of chemicals is used in hazard assessment (e.g. for classification, packaging and labelling), environmental risk assessment (for Chemical Safety Assessment) and persistency assessments (for PBT/ vPvB assessment).