Micropollutant biotransformation and bioaccumulation in natural stream biofilms

Werner L Desiante,Nora S Minas,Kathrin Fenner

doi:10.1016/j.watres.2021.116846

Werner L Desiante, Nora S Minas + Show 1 more

Open Access

https://doi.org/10.1016/j.watres.2021.116846

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Abstract

Micropollutants are ubiquitously found in natural surface waters and pose a potential risk to aquatic organisms. Stream biofilms, consisting of bacteria, algae and other microorganisms potentially contribute to bioremediating aquatic environments by biotransforming xenobiotic substances. When investigating the potential of stream biofilms to remove micropollutants from the water column, it is important to distinguish between different fate processes, such as biotransformation, passive sorption and active bioaccumulation. However, due to the complex nature of the biofilm community and its extracellular matrix, this task is often difficult. In this study, we combined biotransformation experiments involving natural stream biofilms collected up- and downstream of wastewater treatment plant outfalls with the QuEChERS extraction method to distinguish between the different fate processes. The QuEChERS extraction proved to be a suitable method for a broad range of micropollutants (> 80% of the investigated compounds). We found that 31 out of 63 compounds were biotransformed by the biofilms, with the majority being substitution-type biotransformations, and that downstream biofilms have an increased biotransformation potential towards specific wastewater-relevant micropollutants. Overall, using the experimental and analytical strategy developed, stream biofilms were demonstrated to have a broad inherent micropollutant biotransformation potential, and to thus contribute to bioremediation and improving ecosystem health.

Highlights

Worldwide, vast amounts of micropollutants (MPs) enter into natural aquatic environments through various pathways, including run-off from agricultural streams and wastewater treatment plant (WWTP) effluents (Kreuger 1998; Schwarzenbach et al 2006; Margot et al 2015; aus der Beek et al 2016)
They were chosen based on their occurrence in treated wastewater and surface water and expected relevance to surface waters, and to cover multiple use classes
Fenofibrate, gemfibrozil and paracetamol all exhibited high matrix suppression, as recognized from low intensities and bad peak shapes in matrix samples compared to signals from calibration rows

Summary

Introduction

Vast amounts of micropollutants (MPs) enter into natural aquatic environments through various pathways, including run-off from agricultural streams and wastewater treatment plant (WWTP) effluents (Kreuger 1998; Schwarzenbach et al 2006; Margot et al 2015; aus der Beek et al 2016). MPs such as pharmaceuticals, personal care products, artificial sweeteners and pesticides end up in complex mixtures in streams and rivers (Buerge et al 2009). These MPs can pose a risk to human and environmental health (Gavrilescu et al 2015). - and - How does PICT establish in biofilms? One conceivable mechanism leading to PICT in biofilms is the removal of MPs through biotransformation Fenner lying PICT? - and - How does PICT establish in biofilms? One conceivable mechanism leading to PICT in biofilms is the removal of MPs through biotransformation

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Conclusion