title: Short-term transport of glyphosate with erosion in Chinese loess soil--a flume experiment.
abstract: Repeated applications of glyphosate may contaminate the soil and water and threaten their quality both within the environmental system and beyond it through water erosion related processes and leaching. In this study, we focused on the transport of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) related to soil erosion at two slope gradients (10 and 20°), two rates of pesticide with a formulation of glyphosate (Roundup®) application (360 and 720 mg m(-2)), and a rain intensity of 1.0 mm min(-1) for 1 h on bare soil in hydraulic flumes. Runoff and erosion rate were significantly different within slope gradients (p<0.05) while suspended load concentration was relatively constant after 15 min of rainfall. The glyphosate and AMPA concentration in the runoff and suspended load gradually decreased. Significant power and exponent function relationship were observed between rainfall duration and the concentration of glyphosate and AMPA (p<0.01) in runoff and suspended load, respectively. Meanwhile, glyphosate and AMPA content in the eroded material depended more on the initial rate of application than on the slope gradients. The transport rate of glyphosate by runoff and suspended load was approximately 14% of the applied amount, and the chemicals were mainly transported in the suspended load. The glyphosate and AMPA content in the flume soil at the end of the experiment decreased significantly with depth (p<0.05), and approximately 72, 2, and 3% of the applied glyphosate (including AMPA) remained in the 0-2, 2-5, and 5-10 cm soil layers, respectively. The risk of contamination in deep soil and the groundwater was thus low, but 5% of the initial application did reach the 2-10 cm soil layer. The risk of contamination of surface water through runoff and sedimentation, however, can be considerable, especially in regions where rain-induced soil erosion is common.
authors: Institute of Soil and Water Conservation, Northwest A&F University, 712100 Yangling, China; Soil Physics and Land Management, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands; State Key Laboratory of Soil Erosion Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, 712100 Yangling, China. Electronic address: xiaomei.yang@wur.nl.
authors: Xiaomei
authors: X
authors: Yang
authors: Institute of Soil and Water Conservation, Northwest A&F University, 712100 Yangling, China; State Key Laboratory of Soil Erosion Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, 712100 Yangling, China. Electronic address: wafe@ms.iswc.ac.cn.
authors: Fei
authors: F
authors: Wang
authors: Soil Physics and Land Management, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands.
authors: Célia P M
authors: CPM
authors: Bento
authors: Institute of Soil and Water Conservation, Northwest A&F University, 712100 Yangling, China; State Key Laboratory of Soil Erosion Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, 712100 Yangling, China.
authors: Sha
authors: S
authors: Xue
authors: Soil Physics and Land Management, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands.
authors: Lingtong
authors: L
authors: Gai
authors: RIKILT-Institute of Food Safety, Wageningen University, P.O. Box 230, 6700 AE Wageningen, The Netherlands.
authors: Ruud
authors: R
authors: van Dam
authors: RIKILT-Institute of Food Safety, Wageningen University, P.O. Box 230, 6700 AE Wageningen, The Netherlands.
authors: Hans
authors: H
authors: Mol
authors: Soil Physics and Land Management, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands.
authors: Coen J
authors: CJ
authors: Ritsema
authors: Soil Physics and Land Management, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands; Institute of Crop Science and Resources Conservation (INRES), University of Bonn, 53115 Bonn, Germany.
authors: Violette
authors: V
authors: Geissen
mesh_terms: D055593:Geological Phenomena; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis; D006540:Herbicides / Q000032:analysis*; D008956:Models, Chemical; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D000097797:Glyphosate
chemical_list: D005998:Glycine; D006540:Herbicides; D012987:Soil; D012989:Soil Pollutants; D000097797:Glyphosate
keywords: Aminomethylphosphonic acid (AMPA); Glyphosate; Loess; Runoff; Suspended load; Water erosion