The Assessment of Biodegradation and Persistence

Abstract

Testing and assessment strategies for biodegradation and persistence of chemicals and their impact on microbial activity within the framework of environmental legislations are outlined. An integrated assessment concept for biodegradation and persistence of chemicals in the environment is presented, taking into account primary degradation, mineralization and bound residues. Results of simulation tests from soil and water/sediment systems are assigned to four classes of these three criteria and aggregated to an overall assessment resulting in four persistence categories allowing for a more comprehensive estimation of fate and behavior of a chemical in soils, surface waters, and sediments. Examples are given for an application of this assessment concept comparing data sets from simulation studies with plant protection agents in soils and water/sediment systems. The proposed assessment scheme may also be applied for risk assessment in context with registration and notification procedures of any kind of chemical substances by environmental authorities. An assessment scheme is also proposed for the biodegradation and elimination in sewage treatment plants as well as the toxic impact of substances on microbial activity with regard to impaired biodegradation potentials in sewage treatment plants, soils, surface waters, and sediments. Deficiencies and future needs are addressed for achievement of a more realistic risk assessment of fate and behavior of chemicals in the environment.