In the scope of the doctoral thesis, we have comprehensively addressed the issue of environmental pollution with hormones and some other important endocrine disruptor chemicals (EDCs). We found lacking data on the occurrence of many EDCs and their ecotoxicological potential (EP), especially synthetic steroids (SSs). On an example of bisphenol B, we showed that its EP is underestimated by at least four orders of magnitude. Therefore, to evaluate their occurrence in the environment, we have developed an ultra-sensitive analytical method for the quantitative determination of the presence of up to 25 different EDCs from the groups of natural hormones, SSs, and bisphenols. We validated the method according to an extensive protocol, which we also propose for the validation of other environmental analytical methods. We analyzed 36 samples of waste and 33 connected river waters (RW) and successfully quantified 16 EDCs, with the highest concentrations of bisphenols S, A and F, as well as estriol and chlormadinone. Concentrations above the recommended safe values were also determined for estradiol and ethinyl estradiol. Wastewater treatment plants are generally successful in removing most EDCs but achieve on average only 36% reduction in hormonal activity. The presence of BPA, estradiol, BPS and estrone poses a high risk in the majority, and the presence of SS in one tenth of RW samples. In an extensive study, we analyzed another 130 RW samples and determined the increase of EDC burden, which follows an annual cycle, whereby the burden is sixfold higher in winter than in spring. We have also shown that six compounds from our selection pose an environmental risk higher than high risk by at least two orders of magnitude. Additionally, we found that the presence of BPS in drinking water poses a high risk in two-thirds of the 25 samples tested. On the cell line hERα-HeLa-9903, using the additive concentrations model (CAM), we have shown that the estrogenic effects of mixtures follow CAM predictions, while environmental water samples show a lower efficiency than expected. We have also shown that a mixture of compounds at concentrations where their effect is not expected individually, shows measurable effects. Using norethindrone as a model compound, we studied the performance of three different advanced oxidation processes and performed the characterization of transformation products (TPs) that are formed during the degradation processes. All three treatment techniques were effective in reducing the initial concentration of norethindrone, but in vitro, the treated samples showed only a partial decrease or even an increase in estrogenic activity. Therefore, we proposed and experimentally confirmed the formation of 17 TPs, for which we were the first to show only partially reduced and also increased estrogenic activity compared to norethindrone using in silico methods. Additionally, we have confirmed the presence of seven TPs in environmental water samples.
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