Activity of endocrine disrupting compounds in waste water before and after the oxidative treatment of waste water
The increasing entry of pharmaceuticals into surface waters presents a risk for the aquatic environment as well as for humans which led to the definition of numerous international regulations and guidelines. Of particular toxicological interest are pharmaceuticals that were prepared to carry out their biological activity in low concentrations. Endocrine active substances (EAS) belong to this group. It has been shown that these compounds can cause adverse effects in aquatic organisms and also potentially disrupt the hormone system in humans; therefore endocrine disrupting compounds are in the focus of public interest and of current research.
EAS cannot be completely removed in conventional waste water treatment plants. Ozonation as fourth treatment stage has been shown to effectively eliminate those pollutants. However, in hospital waste water in some cases increased endocrine activities were detected after the ozone treatment. It is assumed that antagonists are degraded through ozone treatment, subsequently allowing the agonist substances, for example estrogens, to be active. On the other side, the increased activity can result from the formation of newly formed endocrine substances.
The main focus in this PhD project is on the interaction of different EAS in complex waste water samples (e.g. hospital effluents) and the influence of an advanced waste water treatment. Here, the endocrine activity of waste water (with added endocrine active pharmaceuticals) is analyzed and quantified using the (anti)ER- and (anti)AR-Calux, respectively, and the H295r steroidogenesis assay with ELISA to gain knowledge about the metabolism and mode of action of endocrine disruptors in complex substance mixtures in human cells. Moreover, the prepared samples are chemically analyzed with liquid chromatography tandem mass spectrometry before and after laboratory scale ozonation to investigate the correlation between the degradation of the compounds and a possible reduction of the endocrine activity after this advanced treatment step.