Effects of antimicrobial exposure on detrital biofilm metabolism in urban and rural stream environments

Author/Creator ORCID





Citation of Original Publication

Rikke Jepsen, Ke He, Lee Blaney, Christopher Swan, Effects of antimicrobial exposure on detrital biofilm metabolism in urban and rural stream environments, Science of The Total Environment Volume 666, 20 May 2019, Pages 1151-1160, https://doi.org/10.1016/j.scitotenv.2019.02.254


This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
Access to this item will begin on May 20, 2021.
Attribution-NonCommercial-NoDerivs 3.0 United States


The occurrence of antimicrobials and other pharmaceuticals in streams is increasingly being reported, yet the impacts of these contaminants of emerging concern on aquatic ecosystems are relatively unknown. Bacteria and fungi are vital components of stream environments and, therefore, exposure to antimicrobials may have important consequences for ecosystem services, such as carbon cycling. The objective of this study was to investigate how two antimicrobials, ciprofloxacin and climbazole, impact detrital biofilm metabolism in urban and rural streams. To establish baseline conditions, the biological oxygen demand (BOD) of red maple (Acer rubrum) biofilms was measured in one urban and one rural stream. In mesocosm studies, the BOD of biofilms on singleand mixed-species leaf litter from the same sites was measured after exposure to 10 μg/L of the antimicrobials, both in combination and individually. The presence of ciprofloxacin and climbazole did not affect BOD compared to the controls at the urban site, although significant differences were identified for select treatments at the rural site. In addition, the BOD of mixed-leaf biofilms was not significantly different from that of single species litter after exposure. Overall, exposure to 10 μg/L of the antimicrobials did not significantly impact community-level carbon processing by the leaf biofilms, and leaf mixtures did not result in increased biofilm BOD compared to single species leaves. The outcomes of this work demonstrate a need for further research for the understanding the effects of antimicrobials on rural streams to prevent unintended consequences to ecological processes and biota from future development, leaking septic systems, and wastewater spills.