Review of estimation models for biodegradation

This paper reviews the state-of-the-art of in silico methods for estimating the readily biodegradability of organic chemicals, and describes their (potential) applicability in the identification of chemicals that are persistent or very persistent in the environment, such as Persistent Organic Pollutants (POPs). The paper is based on an in-depth review performed by the European Chemicals Bureau (ECB) of the European Commission's Joint Research Centre in support of the development of technical guidance for the implementation of the Registration, Evaluation, Authorisation of Chemicals (REACH) legislation, and is one of the series of minireviews in this journal. The review covers the most commonly used approaches for estimating the ready biodegradability of organic compounds, such as group contribution approaches, expert systems, probabilistic approaches and hybrid approaches. The main sources of experimental data used to develop the models are also briefly described. The review concludes with an appraisal of the challenges of developing new models and some recommendations are made for further research.