DOI: 10.5194/hess-24-41-2020
论文题名: Hydrological tracers for assessing transport and dissipation processes of pesticides in a model constructed wetland system
作者: Fernández-Pascual E. ; Bork M. ; Hensen B. ; Lange J.
刊名: Hydrology and Earth System Sciences
ISSN: 1027-5606
出版年: 2020
卷: 24, 期: 1 起始页码: 41
结束页码: 60
语种: 英语
Scopus关键词: Fungicides
; Sorption
; Constructed wetlands
; High vertical resolution
; Hydrologic conditions
; Hydrological tracers
; Influence of vegetations
; Temporal and spatial
; Temporal and spatial correlation
; Transformation products
; Wetlands
; bromide
; concentration (composition)
; connectivity
; constructed wetland
; correlation
; experimental study
; pesticide
; sampling
; solute transport
; spatiotemporal analysis
; tracer
; transformation
英文摘要: 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 (Br- ), 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 Br- , 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. © 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/162824
Appears in Collections: 气候变化与战略
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作者单位: Fernández-Pascual, E., Hydrology Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany; Bork, M., Hydrology Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany, Soil Ecology Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany; Hensen, B., Institute of Sustainable and Environmental Chemistry, Leuphana University Lüneburg, Lüneburg, Germany; Lange, J., Hydrology Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany
Recommended Citation:
Fernández-Pascual E.,Bork M.,Hensen B.,et al. Hydrological tracers for assessing transport and dissipation processes of pesticides in a model constructed wetland system[J]. Hydrology and Earth System Sciences,2020-01-01,24(1)