Multi-compartment impact of micropollutants and particularly antibiotics on bacterial communities using environmental DNA at river basin-level

Environmental Pollution, vol. 366, pp. 125487

Abstract

Bacterial communities respond to environmental conditions with diverse structural and functional changes depending on their compartment (water, biofilm or sediment), type of environmental stress, and type of pollution to which they are exposed. In this study, we combined amplicon sequencing of bacterial 16S rRNA genes from water, biofilm, and sediment samples collected in the anthropogenically impacted River Aconcagua basin (Central Chile, South America), in order to evaluate whether micropollutants alter bacterial community structure and functioning based on the type and degree of chemical pollution. Furthermore, we evaluated the potential of bacterial communities from differently polluted sites to degrade contaminants. Our results show a lower diversity at sites impacted by agriculture and urban areas, featuring high loads of micropollution with pesticides, pharmaceuticals and personal care products as well as industrial chemicals. Nutrients, antibiotic stress, and micropollutant loads explain most of the variability in the sediment and biofilm bacterial community, showing a significant increase of bacterial groups known for their capabilities to degrade various organic pollutants, such as Nitrospira and also selecting for taxa known for antibiotic resistance such as Exiguobacterium and Planomicrobium. Moreover, potential ecological functions linked to the biodegradation of toxic chemicals at the basin level revealed significant reductions in ecosystem-related services in sites affected by agriculture and wastewater treatment plant (WWTP) discharges across all investigated environmental compartments. Finally, we suggest transitioning from simple concentration-based assessments of environmental pollution to more meaningful toxic pressure values, measured environmental concentrations normalised by effect information, in order to comprehensively evaluate the role of micropollutants at the ecological (biodiversity) level.

Authors 6

1. Pedro A. Inostroza Aachen Institute for Environmental Research

   RWTH Aachen University · University of Gothenburg

   Affiliation as printed

   Department of Biological and Environmental Sciences, University of Gothenburg, Sweden; Institute for Environmental Research, RWTH Aachen University, Germany. Electronic address: pedro.inostroza@rwth-aachen.de

2. Gerdhard L Jessen

   Austral University of Chile · University of Concepción

   Affiliation as printed

   Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Chile; Center for Oceanographic Research COPAS COASTAL, Universidad de Concepción, Chile

3. Feilong Li

   Guangdong University of Technology

   Affiliation as printed

   Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, China

4. Xiaowei Zhang

   Nanjing University · State Key Laboratory of Pollution Control and Resource Reuse

   Affiliation as printed

   State Key Laboratory of Pollution Control & Resource Reuse, School of the Environment, Nanjing University, China

5. Werner Brack

   Helmholtz Centre for Environmental Research · Goethe University Frankfurt

   Affiliation as printed

   UFZ Helmholtz Centre for Environmental Research, Department Exposome Science, Germany; Department of Evolutionary Ecology and Environmental Toxicology, Goethe University Frankfurt, Germany

6. Thomas Backhaus Aachen Institute for Environmental Research

   RWTH Aachen University · University of Gothenburg

   Affiliation as printed

   Department of Biological and Environmental Sciences, University of Gothenburg, Sweden; Institute for Environmental Research, RWTH Aachen University, Germany