| The increasing worldwide contamination of aquatic ecosystems with thousands of man-made organic micropollutants (OMPs) is one of the key environmental problems facing humanity today. Every year ~300 million tons of >100 000 synthetic OMPs are used for production of industrial and consumer products. Large amounts of OMPs continuously reach natural waters, primarily through industrial activities and municipal and industrial wastewater effluents. The released OMPs can accumulate in the food chain, cause lethal and sub-lethal ecotoxicological effects, alter ecosystem functioning, reduced biodiversity, and constrain the ecosystem services. However, today’s target detection methods measure only a small fraction of the released OMPs (‘the tip of the iceberg’), while the vast number of pollutants remain unknown. This poses a vast risk for the ecosystem and human health. In this project, we will use suspect and non-targeted screening methods for an early detection of OMPs in the aquatic ecosystem focusing on Lake Mälaren, which is the third largest fresh water ecosystem and the largest drinking water reservoir in Sweden. The suspect and non-targeted screening approach, which has been recently developed in our research group, has the advantage over target screening methods that this enables to screen for a vast number of OMPs simultaneously based on high resolution mass spectrometry. In this project, we will apply this new approach to screen for OMPs in i) potential source areas (e.g wastewater effluents), ii) freshwater, iii) sediment and iv) biota (e.g. mussels) in Lake Mälaren. The sampling will be conducted in a close collaboration with the Lake Mälaren's Water Conservation Association (Mälarens vattenvårdsförbund). After sampling and sample enrichment, our already-established workflow includes the following steps: a) instrumental analysis using high resolution mass spectrometry, b) data processing based on blank subtraction, retention time, fragments, isotopes, mass defect, time/special trends, PCA/clustering, c) prioritization based on databases and suspect screening. A good prioritization strategy is a key part since each sample can include thousands of peaks, each representing suspect OMPs. Hereby, this project will greatly benefit from Swedish Chemicals Agency's (KemI) product register, an unique database for the use of chemicals in Sweden. Finally, the identified OMPs will be characterized by their persistence, bioaccumulation, toxicity (PBT) potential and their environmental fate in the ecosystem (i.e. water, sediment, biota). Ultimately, this project will produce a list of prioritized pollutants for which control measures are urgently needed in the future. The knowledge gained from this project will improve the protection of the aquatic ecosystem and reduce their exposure to toxic OMPs. |