Abstract:
Anthropogenic contaminants are ubiquitous in the environment. These environmental pollutants enter the environment via various entry path for example wastewater treatment plants or pesticide application in agriculture. Released into the environment some are detected in surface waters. The environmental fate of contaminants depends on their physicochemical properties and on the local conditions. Contaminants may be transformed by biotic or abiotic processes like photo-transformation or hydrolysis. Aquatic organisms are exposed to contaminants which are present in water. To analyze trace amounts of contaminants in surface waters preconcentration and cleanup techniques are required to enable their detection with sensitive methods like mass spectrometry. Especially, the analysis of ionic and ionizable compounds is challenging and these compounds come more into focus as many metabolites are more polar than the parent compounds. In this thesis, electrophoretic techniques were investigated for their ability to fractionate and preconcentrate wastewater chemicals. Two different free flow modes were applied to surface water samples and an HPLC-MS method was developed for identification and quantification of 92 chemicals relevant in wastewater in the low ng/L range. In a second approach the impact of experimental conditions on the preconcentration of ionic analytes by electrophoretic techniques was investigated.
Aquatic organism are exposed to chemicals present in surface waters and in case of benthic living organisms additionally to sediment bound contaminants. Some of these chemicals are taken up by the organisms and may pose adverse effects. Incorporated chemicals might be metabolized, accumulated or excreted by the organisms. Bioaccumulation leads to higher concentrations in the organisms than in the surrounding water. Therefore, the analysis of xenobiotics in organisms is of special interest to detect compounds of concern as well as to more precisely predict the environmental behavior of compounds. In this thesis, extraction and quantification of the contaminants and their transformation products were achieved based on QuEChERS extraction and following analysis by HPLC-MS. The method was applied to different organisms from exposure experiments. For the pharmaceutical carbamazepine a quantification method was developed to analyze the internal concentration in Chironomus riparius larvae and adult midges in the low ng/g range. The method was applied to assess the transfer of the pharmaceutical from aquatic to terrestrial stages and thus the transfer to the terrestrial ecosystems. Analysis of larvae and midges from emergence studies indicated a transfer of 100 % carbamazepine body burden from larvae to midges. The developed method for analysis of the neonicotinoid thiacloprid was needed only 5 Chironomus riparius larvae and enabled quantification with a limit of detection of 12 ng/g wet weight. A third procedure was developed to analyze the fungicide propiconazole and three of its metabolites in fungi mycelium in the low ng/g range. To assess the impact of sorption to nanoparticles on the environmental fate of the chemicals, thiacloprid and propiconazole were quantified in larvae and fungi which were exposed to the pesticide in the presence of nanoparticles, which were demonstrated to sorb the pesticide. Analysis of thiacloprid residues larvae revealed equal concentrations in experiments independent from nanoparticles. Reduced transformation of propiconazole in fungi experiments was detected depending on the nanoparticle concentration in liquid culture experiments and reduced propiconazole uptake in experiments on agar plates. The analysis of different fungi species revealed strong inter species differences in and uptake and metabolism of the fungicide.
bioaccumulation