Using recirculating flumes and a response surface model to investigate the role of hyporheic exchange and bacterial diversity on micropollutant half-lives

authored by
Anna Jaeger, Claudia Coll, Malte Posselt, Jonas Mechelke, Cyrus Rutere, Andrea Betterle, Muhammad Raza, Anne Mehrtens, Karin Meinikmann, Andrea Portmann, Tanu Singh, Phillip J. Blaen, Stefan Krause, Marcus Andreas Horn, Juliane Hollender, Jonathan P Benskin, Anna Sobek, Jörg Lewandowski

Enhancing the understanding of the fate of wastewater-derived organic micropollutants in rivers is crucial to improve risk assessment, regulatory decision making and river management. Hyporheic exchange and sediment bacterial diversity are two factors gaining increasing importance as drivers for micropollutant degradation, but are complex to study in field experiments and usually ignored in laboratory tests aimed to estimate environmental half-lives. Flume mesocosms are useful to investigate micropollutant degradation processes, bridging the gap between the field and batch experiments. However, few studies have used flumes in this context. We present a novel experimental setup using 20 recirculating flumes and a response surface model to study the influence of hyporheic exchange and sediment bacterial diversity on half-lives of the anti-epileptic drug carbamazepine (CBZ) and the artificial sweetener acesulfame (ACS). The effect of bedform-induced hyporheic exchange was tested by three treatment levels differing in number of bedforms (0, 3 and 6). Three levels of sediment bacterial diversity were obtained by diluting sediment from the River Erpe in Berlin, Germany, with sand (1 : 10, 1 : 1000 and 1 : 100 000). Our results show that ACS half-lives were significantly influenced by sediment dilution and number of bedforms. Half-lives of CBZ were higher than ACS, and were significantly affected only by the sediment dilution variable, and thus by bacterial diversity. Our results show that (1) the flume-setup is a useful tool to study the fate of micropollutants in rivers, and that (2) higher hyporheic exchange and bacterial diversity in the sediment can increase the degradation of micropollutants in rivers.

Institute of Microbiology
External Organisation(s)
Humboldt-Universität zu Berlin
Stockholm University
Swiss Federal Institute of Aquatic Science and Technology (Eawag)
ETH Zurich
University of Bayreuth
University of Padova
Technische Universität Darmstadt
IWW Rheinisch-Westfälisches Institut für Wasserforschung gemeinnützige GmbH
Carl von Ossietzky University of Oldenburg
Colorado School of Mines
University of Birmingham
Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB)
Environmental science. Processes & impacts
No. of pages
Publication date
Publication status
Peer reviewed
ASJC Scopus subject areas
Environmental Chemistry, Public Health, Environmental and Occupational Health, Management, Monitoring, Policy and Law
Sustainable Development Goals
SDG 3 - Good Health and Well-being
Electronic version(s) (Access: Open) (Access: Open)