Discharge and fate of biocide residuals to ephemeral stormwater retention pond sediments

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Biocides used in paints and renders prevent algae and fungi growth but can wash off during wind-driven rain and enter urban environments. Retention ponds represent part of stormwater management that retain water and partly pollutants. However, it is poorly understood which percentage of biocides leached from facades reaches a pond and how efficiently biocides are retained inside ponds although biocides can have harmful environmental effects. Here, we combined measurements and modeling to address diffuse biocide loss and a pond's retention capacity in a delimited residential area of 3 ha, with detached houses connected to an ephemeral retention pond. Six stormwater events were sampled within 2 years and confirmed biocidal residuals at pond inflow. Model results revealed that during the sampled events only 11% of terbutryn leachate arrived at the pond while the major part of this biocide was diffusely lost in the residential area. Measured low terbutryn concentrations in the sediment (mean 2.6 ng g−1) confirmed this result. Model results suggested that approximately 50% of terbutryn reaching the pond were retained and degraded. Our results are site-specific but suggest that biocide retention in ponds is limited, environmental entry pathways are diverse and that biocide use should be limited at its source.
Original languageEnglish
JournalHydrology Research
Volume53
Issue number11
Pages (from-to)1441-1453
Number of pages13
ISSN1998-9563
DOIs
Publication statusPublished - 01.11.2022

Bibliographical note

Funding Information:
We would like to acknowledge Lennart Lisy for taking samples in the spring 2020 and the team of sedimentology in Freiburg especially Alicia Sullivan for the sediment analysis. We thank Michael Burkhardt and his team for providing support with the software COMLEAM, Andreas Steinbrich for finding and helping to prepare the GIS data for modeling and Tobias Junginger for helpful discussions. Stadt Landau and David Elsässer kindly provided GIS data and aerial images. Further GIS data were obtained via OpenStreetMap and 3D Rheinland-Pfalz. A student course from the University of Landau recorded the GIS data regarding surface types in more detail. Different soil parameters were provided by Bundesanstalt für Geowissenschaften und Rohstoffe and the digital elevation model by Landesamt für Vermessung und Geobasisinformation Rheinland-Pfalz. This research was funded by the EU within the European Regional Development Fund (ERDF), to support measure INTER-REG V in the Upper Rhine as part of the NAVEBGO project 5.3 (sustainable reduction of biocide inputs to groundwater in the Upper Rhine region). We acknowledge support by the Open Access Publication Fund of the University of Freiburg.

Publisher Copyright:
© 2022 The Authors.

    Research areas

  • biocides, retention pond, terbutryn, transformation products, urban stormwater management
  • Chemistry

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