Effect-directed analysis of surface and waste water

Michelle Klein, IUTA

The contamination of aquatic systems with micropollutants is one of the biggest challenges of the water cycle. In order to check the water quality or control treatment steps it is not only important to identify compounds and potential transformation products but also their biological effects. Effect-based methods (EBMs) make it possible to analyse the impact of single micropollutants and also complex mixtures with regard to a broad range of endpoints. Especially the investigation of mixtures is crucial as micropollutants in the environment always occur in complex matrix compositions together with other contaminants. This can substantially alter the potential toxicological impact compared to single substance results. The effect-directed analysis is therefore a suitable approach for the holistic investigation and observation of water quality without the need to analyse single compartments separately. In combination with instrumental analytics, it is possible to identify potential sources of contamination.

Within the scope of this project a combination of effect-directed and instrumental analytics for the monitoring of micropollutants in surface and waste waters will be applied. Therefore, various streams with different input scenarios will be investigated via effect-based methods which are based on receptor activation of transgene yeast cells or enzyme inhibition. Additionally, the influence of rain events on water quality and micropollutant patterns will be controlled, especially with regard to combined sewer overflows. Thus, a wide range of bioactive substances and their cumulative effect can be assessed, where the focus will be laid on different, toxicologically relevant endpoints namely endocrine active substances and acetylcholine esterase inhibitors. Additionally, the evaluation will be accompanied by GC- and LC-MS analysis.

The monitoring comprises a surface water before and after the start of direct discharge of new kind of waste water treatment plant directly implemented at a hospital site. In the context of the implementation of the pilot plant every treatment step will be evaluated via effect-based methods (endocrine disruptor, acetylcholine esterase inhibition, aryl hydrocarbon receptor). Another crucial point for the treatment of hospital waste water is the elimination of antibiotic residues from the water cycle, which can accelerate the formation of antibiotic resistance. For that reason, the occurrence of different classes of antibiotics before and after the implementation is as well analysed with the aid of a new reporter gene assay.