Development of a single biofilm extraction method for non-target analysis and bioassays to monitor wastewater micropollutants

Abstract

International audiencePassive samplers (PS) are strong tools to monitor micropollutants due to their ability to accumulate andconcentrate the pollutants present in water. Among existing PS, those using biofilms as a receiving phasehave gained interest for environmental monitoring, notably in waste water, for which conventional PS arelimited by biofouling. Extraction and (bio)analysis of contaminants adsorbed in biofilms still needoptimisation in monitoring context. Non-target analysis has been increasingly used during the last decadeto detect a large range of water micropollutants, including emerging contaminants, which positions it as agreat tool for environmental monitoring. However, this method does not account for the biologicalactivities of the compounds, and the impact of mixture effects on their activity. Hence, as acomplementary approach, in vitro bioassays provide a global bioactivity profile of the water sampleswhile considering all the bio-active micropollutants and their potential mixture effect. The combination ofPS with bioassays and chemical analysis has already shown its effectiveness in characterizing water.This work aims to develop an approach based on the coupling of an innovative biofilm -based PS withnon-target screening and in vitro bioassays to characterize wastewater. This presentation will mainly focuson the development a single biofilm extraction method for both non -target analysis and bioassays,allowing us to have a robust correlation between the compounds analysed and the activity measured.Several solvents, extraction methods, and clean-up strategies were implemented and compared for biofilmextraction. The extracts were then subjected to chemical analysis and in vitro bioassays. For the chemicalanalysis performed on a liquid chromatography coupled to a high-resolution mass spectrometry, theextraction efficiency was evaluated based on characteristics such as standard recoveries, number ofcommon and specific compounds detected with suspect screening, number of common and specificunknown features detected, and range of molecular weight or polarity. For bioassays, the evaluations wereassessed on the response of four nuclear receptors (estrogenic, androgenic, pregnane X, and arylhydrocarbon receptors).Based on the outcome of the results obtained for these tests, a single extraction protocol offering the bestefficiency compromise for both chemical analysis and in vitro bioassays will be presente