Hydrological tracers for assessing transport and dissipation processes of pesticides in a model constructed wetland system

Research output: Journal contributionsJournal articlesResearchpeer-review

Authors

Studies that have used hydrological tracers to investigate the fate and transport of pesticides in constructed wetlands have often considered such systems as a "black box". Consequently, internal temporal and spatial mechanisms that dominate pesticide transport and dissipation (e.g., sorption, transformation and plant uptake) are still not fully understood. Here we present a novel approach that combines the use of tracers with different sorptive and reactive properties - i.e., bromide (<span classCombining double low line"inline-formula">Br-</span>), uranine (UR) and sulforhodamine B (SRB) - with high vertical resolution sampling and monitoring to evaluate transport and dissipation processes of three selected pesticides (boscalid, penconazole and metazachlor) inside a model constructed wetland system on a long-term basis and detailed spatial scale. Moreover, the influence of vegetation and alternating different hydrologic conditions on transport and dissipation processes was evaluated by comparing a vegetated with a non-vegetated section and by alternating periods of saturation and drying. Breakthrough curves obtained at different sampling depths pointed out that the solutes were not equally distributed within the constructed wetland. Data revealed that a higher mass of solutes was transported to the vegetated part of the uppermost layer, which was associated with possible lateral transport at or near the surface and/or a shortcut effect produced by the roots. In contrast, the middle layers showed retardation, most likely due to the presence of water-filled pores before the injections and low pore connectivity in the vicinity of the sampling ports. The strong temporal and spatial correlation found between <span classCombining double low line"inline-formula">Br-</span>, UR and metazachlor indicated that transport was the dominant process for these solutes. Conversely, SRB, boscalid and penconazole most likely underwent sorption, as evidenced by their absence in the middle layers, the rapid decrease in their concentrations after the injections and the gradual increase in accumulated mass recovery at the outlet. The overall tracer mass balance allowed us to identify three dissipation pathways: sorption, transformation and plant uptake. The detection of metazachlor transformation products (TPs) confirmed the contribution of transformation to metazachlor dissipation, whereas no TPs for boscalid and penconazole were detected; however, their transformation could not be ruled out in the present study. Hot spots of sorption and transformation were found in the uppermost layer, whereas hot moments were detected at the beginning of the experiment for sorption and after promoting aerated conditions for transformation. The use of hydrological tracers coupled with high vertical resolution sampling and monitoring proved to provide valuable information about the transport vectors and dissipation processes of pesticides inside a constructed wetland. This study represents a first approximation, and further experiments need to be carried under field conditions in combination with modeling.

Original languageEnglish
JournalHydrology and Earth System Sciences
Volume24
Issue number1
Pages (from-to)41-60
Number of pages20
ISSN1027-5606
DOIs
Publication statusPublished - 08.01.2020

Bibliographical note

Publisher Copyright:
© 2020. This work is distributed under the Creative Commons Attribution 4.0 License.

Documents

DOI

Recently viewed

Publications

  1. Health and the intention to retire: exploring the moderating effects of human resources practices
  2. Integrating a piezoelectric actuator with mechanical and hydraulic devices to control camless engines
  3. Modeling of microstructural pattern formation in crystal plasticity
  4. The means determine the end
  5. ICT knowledge absorptive capacity: A critical factor for technology integration in schools
  6. Curatorial Practices of the ‘Global’
  7. Fragmentierung und Kooptation
  8. Effect of salinity-changing rates on filtration activity of mussels from two sites within the Baltic Mytilus hybrid zone
  9. The Exilic Classroom
  10. Intricate Letters and the Reification of Light
  11. Towards Ecosystems for Responsible AI
  12. Why the measurement of species diversity requires prior value judgements
  13. Telomere length is a strong predictor of foraging behavior in a long-lived seabird
  14. Changes in the Work Situation and Attitudes in East-germany After the Introduction of Capitalism
  15. Progress and challenge for magnesium alloys as biomaterials
  16. A Decision Support System for Crew Rostering in Public Transit
  17. Entangled Identities
  18. Mindfulness as self-confirmation? An exploratory intervention study on potentials and limitations of mindfulness-based interventions in the context of environmental and sustainability education
  19. Explorations in social spaces
  20. Transgressive Use of Technology
  21. A switching model predictive control for overcoming a hysteresis effect in a hybrid actuator for camless internal combustion engines
  22. Putting inquiry-based learning into practice
  23. Organizing for innovation through accelerators: An introduction
  24. Sustainability in Business: Integrated Management of Value Creation and Disvalue Mitigation
  25. Pathways towards sustainable and just futures with and for disabled populations
  26. Who wants to take an intelligence test? Personality and achievement motivation in the context of ability testing
  27. Diversity and specificity of host-natural enemy interactions in an urban-rural interface
  28. CSR communication on corporate websites compared across continents
  29. A new and benign hegemon on the horizon?
  30. High temperature deformation mechanisms and processing map for hot working of cast-homogenized Mg-3Sn-2Ca alloy
  31. Impact of prescribed burning on the nutrient balance of heathlands with particular reference to nitrogen and phosphorus
  32. Incremental analysis of springback and kinematic hardening by the variation of tension during deep drawing
  33. Advancing Decision-Visualization Environments—Empirically informed Design Recommendations
  34. A single PD plus gravity compensation control for global asymptotic regulation of robot manipulators with actuator constraints
  35. Augmented space
  36. Symmetry in Spatial Perspective Tasks