Risk assessment of mixtures and transformation products


Transformation products stem from micropollutants that have undergone chemical reactions in the human body or in animals (metabolites), in the environment by biotic and abiotic processes (degradates) and by technical processes from natural precursors (disinfection by-products). Little is known about which and how many transformation products are formed, in what quantities and what level of harm they may cause. In order to complement classical exposure-driven approaches for the identification of transformation products, we have recently proposed an effect-driven approach to test the mixture effect of chemicals undergoing a transformation process and only to proceed to identification of chemical structure if relevant transformation products are formed, which is indicated when toxicity does not decrease proportionally with the concentration of the parent. In this research topic we work in collaboration with engineers and microbiologist in natural and engineered systems on processes such as biodegradation, photodegradation and chemical oxidation such as ozonation and chlorination.