Suchergebnisse

An drei Modellstandorten mit Umkehrosmoseanlagen für die zentrale Enthärtung von Trinkwasser mit Konzentratableitung in Flüsse wurde der Zustand der Gewässer vor und nach Beginn der Konzentrateinleitung dokumentiert. An den Modellstandorten lagen aufgrund des relativ hohen Konzentratanteils ungünstige Bedingungen in Hinblick auf mögliche Veränderungen der Gewässerbeschaffenheit vor. Bei den physikalisch-chemischen Parametern war zu erkennen, dass saisonale Faktoren einen größeren Einfluss auf die Fließgewässerbeschaffenheit ausüben als die Konzentrat einleitung. Die in Konzentraten enthaltenen Antiscalantwirkstoffe führten jedoch zu einem signifikanten Anstieg der Konzentrationen dieser Wirkstoffe im Gewässer. Makrozoobenthos und Diatomeen haben sich in den drei Modellgewässern sowohl in quantitativer als auch in qualitativer Hinsicht als Folge der Konzentrateinleitung nicht wesentlich verändert. Unter den Bedingungen des Modellprojektes war die Einleitung von Konzentraten in Fließgewässer ökologisch verträglich, auch wenn aus Minimierungsgründen die Konzentrateinleitung in Flüsse zu diskutieren ist.

AbstractLaboratory tests and column tests were carried out in a waterwoks to investigate the removal of short- and long-chain PFAS using activated carbon filtration and ion exchange treatment. For all adsorbents, the sorption affinity of short-chain per- and polyfluoroalkyl carboxylic acids (PFCA) was significantly lower than that of long-chain PFAS or short-chain per- and polyfluoroalkyl sulfonic acids (PFSA). In the PFAS-polluted groundwater matrix, the short-chain PFCA PFBA and PFPeA could only be sufficiently removed with activated carbon over short run times of 6000 and 11,000 bed volumes (BV), respectively. Longer PFCA with a chain length of C6 or more were removed over longer run times.The removal of short-chain PFCA using ion exchange media could also only be achieved over relatively short run times of 5000 BV for PFBA, 10,000BV for PFPeA and 18,000 BV for PFHxA. These are sometimes significantly longer than those of activated carbon. Due to the higher material costs for ion exchange media, there are nevertheless no lower operating costs when the ion exchangers are used in single-use mode. However, ion exchangers can be regenerated and then reused which can result in economic advantages compared to activated carbon filtration. However, for the extensive regeneration, especially for the elution of the long-chain PFAS, the additional use of ethanol is needed in the process. In contrast, the short-chain PFBA and PFPeA can be extracted without organic solvent from a weakly basic ion exchanger.

The environmental risk assessment (ERA) focusses on individual chemicals, while non-target organisms in the environment are exposed simultaneously to a multitude of substances from various sources. In the aquatic environment, effluents of wastewater treatment plants (WWTPs) represent a key source for co-incidental mixtures of chemicals from various uses. The aim of the present project was to explore the consideration of mixtures of chemicals released via WWTPs in an ERA. Based on a literature survey and own data on human pharmaceuticals and other substances typically present in the effluents of WWTPs, 20 substances were selected. In total, 33 single-substance and 24 mixtures were assessed in chronic toxicity tests with cyanobacteria, green algae, the water plant Lemna minor and the freshwater crustacean Daphnia magna. The results from the mixture tests provided consistent evidence that the aquatic toxicity of mixtures with regard to chronic endpoints can be predicted by the concept of concentration addition (CA) with less than 3-fold deviation. Evidence for synergistic interaction with respect to CA of the two antibiotics sulfamethoxazole and trimethoprim in primary producers was detected, which calls for further investigations. Furthermore, mixture tests demonstrated that the presence of 50% (v:v) WWTP effluent in the test medium did not impact the predictability of mixture toxicity. With regard to mixture concentrations changing during the exposure time, as it is typical for WWTP effluents, the average mixture concentrations appeared to underestimate chronic mixture effects on reproduction of D. magna, while the peak concentrations provided a better estimate. Single-substance risk assessments were compared to risk assessments for selected mixture scenarios based on different approaches. A mixture assessment factor applied in the ERA of single substances and its appropriate size is discussed in view of a prospective consideration of environmental mixtures of unknown composition in the single-substance ERA.

As tools for environmental monitoring of pharmaceuticals, mode of action (MOA)-based in vitro-assays were developed for beta-blockers, as e.g. metoprolol, and non-steroidal anti-inflammatory drugs (NSAIDs), as e.g. diclofenac. For this purpose stable cell lines were generated which expressed recombinant MOA-based sensing and reporting units allowing for rapid live-cell visualization of immediate fluorescence signal changes. Sensitive cell based assays developed in microtiter plate format facilitated the quantitative determination of metoprolol and diclofenac activities in effluents of wastewater treatment plants. In order to validate these tests for their suitability to reflect in vivo-effects in environmentally relevant aquatic organisms, toxicity tests and biomarker studies were conducted with fish (brown trout), crustaceans (gammarids, daphnia), snails and sediment-dwelling invertebrates (annelids). Test were conducted (1) in the laboratory under controlled experimental conditions with isolated substances and binary mixtures, (2) in aquatic mesocosms and (3) under field conditions in a bypass-system connected to the effluent of a municipal wastewater treatment plant. In addition to population relevant endpoints as e.g. reproduction, development or fertility, also individual health parameters were investigated by means of stress protein analyses, histological investigations and studies revealing the oxidative stress status of the exposed organisms.