Wastewater microorganisms impact the micropollutant biotransformation potential of natural stream biofilms. (15th June 2022)

• Record Type: Journal Article
• Authors: Desiante, Werner L.; Carles, Louis; Wullschleger, Simon; Joss, Adriano; Stamm, Christian; Fenner, Kathrin
• Is Part Of: Water research. Volume 217(2022)
• Publication Date: 2022-06-15
• Subjects: Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2022.118413
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Treated wastewater affects biotransformation potential of downstream river biofilms. Degradation functions emerge in WWTP in response to high contaminant concentrations. Increased downstream biotransformation caused by release of adapted microorganisms. Increased downstream biotransformation not caused by exposure to contaminants. WWTP effluents change ecological function of downstream biofilms. Abstract: Biotransformation is the most important process removing manmade chemicals from the environment, yet mechanisms governing this essential ecosystem function are underexplored. To understand these mechanisms, we conducted experiments in flow-through systems, by colonizing stream biofilms under different conditions of mixing river water with treated (and ultrafiltered) wastewater. We performed biotransformation experiments with those biofilms, using a set of 75 micropollutants, and could disentangle potential mechanisms determining the biotransformation potential of stream biofilms. We showed that the increased biotransformation potential downstream of wastewater treatment plants that we observed for specific micropollutants contained in household wastewaters ( downstream effect ) is caused by microorganisms released with the treated effluent, rather than by the in-stream exposure to those micropollutants. Complementary data from 16S rRNA amplicon-sequencing revealed 146 amplicon sequence variants (ASVs) that followed the observed biotransformation patterns. Our results align with findings for community tolerance, and provide clear experimental evidence that microorganisms released with treated wastewater integrate into downstream biofilms and impact crucial ecosystem functions.