Suchergebnisse

Protection of freshwater ecosystems from organic pollutants is important to preserve biodiversity and the goods they provide to society, such as clean drinking water and recreation. Organic chemicals have been shown to adversely impact freshwater ecosystems in local and regional studies. Nevertheless, due to paucity of studies on larger spatial scales, it remains unknown how widespread the risk from organic chemicals is. For the first time, to our knowledge, we provide strong evidence that chemicals threaten the ecological integrity and consequently the biodiversity of almost half of the water bodies on a continental scale, based on the analysis of governmental monitoring data from 4,000 European sites. Due to limitations associated with the monitoring programs, our results are likely to underestimate the actual risks.

Abstract

Background
The Max Weaver Dye Library (MWDL) from North Carolina State University is a repository of around 98,000 synthetic dyes. Historically, the uses for these dyes included the coloration of textiles, paper, packaging, cosmetic and household products. However, little is reported about their ecotoxicological properties. It is anticipated that prediction models could be used to help provide this type information. Thus, the purpose of this work was to determine whether a recently developed QSAR (quantitative structure–activity relationships) model, based on ACO-SVM techniques, would be suitable for this purpose.


Results
We selected a representative subset of the MWDL, composed of 15 dyes, for testing under controlled conditions. First, the molecular structure and purity of each dye was confirmed, followed by predictions of their solubility and pKa to set up the appropriate test conditions. Only ten of the 15 dyes showed acute toxicity in Daphnia, with EC50 values ranging from 0.35 to 2.95 mg L−1. These values were then used to determine the ability of the ACO-SVM model to predict the aquatic toxicity. In this regard, we observed a good prediction capacity for the 10 dyes, with 90% of deviations within one order of magnitude. The reasons for this outcome were probably the high quality of the experimental data, the consideration of solubility limitations, as well as the high purity and confirmed chemical structures of the tested dyes. We were not able to verify the ability of the model to predict the toxicity of the remaining 5 dyes, because it was not possible to determine their EC50.


Conclusions
We observed a good prediction capacity for the 10 of the 15 tested dyes of the MWDL, but more dyes should be tested to extend the existing training set with similar dyes, to obtain a reliable prediction model that is applicable to the full MWDL.

Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The Water Framework Directive (WFD) and its daughter directives are the major body of legislation for the protection and sustainable use of European freshwater resources. The practical implementation of the WFD with regard to chemical pollution has faced some challenges. In support of the upcoming WFD review in 2019 the research project SOLUTIONS and the European monitoring network NORMAN has analyzed these challenges, evaluated the state-of-the-art of the science and suggested possible solutions. We give 10 recommendations to improve monitoring and to strengthen comprehensive prioritization, to foster consistent assessment and to support solution-oriented management of surface waters. The integration of effect-based tools, the application of passive sampling for bioaccumulative chemicals and an integrated strategy for prioritization of contaminants, accounting for knowledge gaps, are seen as important approaches to advance monitoring. Including all relevant chemical contaminants in more holistic "chemical status" assessment, using effect-based trigger values to address priority mixtures of chemicals, to better consider historical burdens accumulated in sediments and to use models to fill data gaps are recommended for a consistent assessment of contamination. Solution-oriented management should apply a tiered approach in investigative monitoring to identify toxicity drivers, strengthen consistent legislative frameworks and apply solutions-oriented approaches that explore risk reduction scenarios before and along with risk assessment.