Development and validation of high- resolution mass spectrometry-based approaches for active and passive sampling of emerging organic micropollutants in the marine environment

Nowadays, a growing societal and scientific concern exists regarding the widespread occurrence of potential endocrine disrupting compounds (EDCs) in the aquatic environment. The most important potential EDC classes comprise the steroid hormones, plasticizers and plastics additives. Indeed, even at very low concentrations, steroidal EDCs may affect the hormonal system of aquatic organisms, while leaching of plasticizers and plastics additives into the aquatic environment is inevitable as a result of their extensive use in numerous applications. Until now, limited knowledge was available on the presence of steroidal EDCs, plasticizers and plastics additives in the marine environment. Therefore, an urgent need existed to monitor the fate and effects, as well as the environmental and human risks posed by these emerging micropollutants in marine ecosystems. Given our lack of knowledge on the occurrence of EDCs, the main goal of this dissertation was to investigate the prevalence of steroidal EDCs, plasticizers and plastics additives in the marine environment. To this end, new analytical methods targeting a broad range of compounds (n=97) were developed, optimized and validated. Not only instantaneous sampling techniques were examined, but also novel long-term sampling techniques were investigated (i.e.: active and passive sampling). Both were applied extensively in the Belgian Part of the North Sea (BPNS), from 2016 to 2018. Finally, the potential negative effects of the detected concentrations were assessed. Chapter I entails a comprehensive overview on the fate of EDCs in the aquatic environment. Additionally, a summary on the predominant analytical strategies employed for sampling, extraction and detection of EDCs is provided, including a detailed description of the analytical platforms and their capabilities. This chapter ends with the conceptual framework and research objectives of this PhD study, as outlined in research chapters II, III and IV. The aim of chapter II was to develop and validate two accurate ultra-high performance liquid chromatography (UHPLC) coupled to high-resolution mass spectrometry (HRMS) methods for the quantification of steroidal EDCs (n=70), plastics additives and plasticizers (n=27) in seawater. For each target group, the instrumental methods were combined with optimised large-volume solid phase extraction procedures, as it was the goal to detect residues in the marine environment. The developed methods showed excellent performance characteristics (according to 2002/657/EC and Eurachem guidelines) and versatility to fresh water samples. In chapter III, a new sorbent phase for passive sampling purposes was investigated that enables to capture a broad polarity range of emerging organic compounds (log P range between 1.30 to 9.85). For 131 compounds the sampler-water partition coefficients (Ksw) could be determined by using a static exposure design. Calculation of the thermodynamic parameters indicated that the main partitioning process for the (alkyl)phenols, personal care products, pesticides and pharmaceuticals was driven by physisorption, while the uptake of phthalates and steroidal EDCs was mediated by a combination of physisorption and chemisorption. It was clearly demonstrated in this chapter that hydrophilic divinylbenzene can be used for passive sampling. Using the newly developed methodologies from chapters II and III, active and passive samplers were intensively deployed in the Belgian Part of the North Sea, as discussed in chapter IV. The detected concentrations for the steroidal EDCs were mainly below 10 ng L-1, while for the plastics additives and plasticizers concentrations between 10 and 1000 ng L-1 were observed. Concentrations detected by passive sampling, were generally lower than those in active samples. Furthermore, it could be concluded that our proposed strategy for active and passive sampling offers a complementary approach for the measurement of potential EDCs in the marine environment. Ultimately, a risk assessment was performed to investigate the potential risks of the detected compounds to aquatic organisms. Finally, in chapter V, the general discussion and future perspectives of this PhD study are presented. Thereby, it was suggested that future research should focus on the implementation and use of an automized analysis pipeline for suspect and untargeted screening. Also, the development of new passive samplers containing hydrophilic DVB could be promising, as Speedisks showed reduced Ksw as compared to naked sorbent. Moreover, Speedisks could serve as a viable archive tool for sampled EDCs, but this should be investigated more extensively. Finally, a more in-depth evaluation of contaminant levels in Speedisk passive samplers as compared to those in biota could offer an added value towards environmental risk assessment of the findings obtained in this PhD. Overall, this thesis contributes to the establishment of integrated active and passive sampling approaches for monitoring potential EDCs in the marine environment, and more specifically the BPNS.

Publication year:2019

Accessibility:Open