Abstract

Fluroxypyr is an auxin-type herbicide used for postemergent control of broad-leaved weeds in agriculture and in nonagricultural environments such as railways. The overall aim of this study was to assess the potential environmental impact from fluroxypyr application to railway tracks and to elucidate some of the factors that control its environmental fate. In laboratory studies, we examined the degradation of fluroxypyr and the formation of its metabolites fluroxypyr-methoxypyridine (F-MP) and fluroxypyr-pyridinol (F-P) in soil from two Swedish railways. We also investigated the degradation and leaching of fluroxypyr in three different railway plots treated with fluroxypyr (360 g at ha(-1)). The half-life of fluroxypyr in soil samples ranged between 28 and 78 d. An estimated mean 48.6 +/- 20% of the fluroxypyr was converted into F-P and 8.0 +/- 2% into F-MP. The main metabolite, F-P, was rapidly degraded, with an average half-life of 10 +/- 5 d. However, F-MP was not degraded to a significant degree in any sample, resulting in slowly increasing concentrations throughout the experiment. This pattern of relatively rapid degradation of F-P and slow accumulation of F-MP was also observed in the field. The persistent nature of F-MP may be of concern if fluroxypyr is used repeatedly at the same location. Fluroxypyr was detected in the groundwater beneath the track at all three locations studied in concentrations exceeding the EU limit of 0.1 mu g L-1 for pesticides in drinking water, and F-P was detected in the groundwater at two of three locations. The most important factor controlling fluroxypyr degradation rate in soil was the soil water content, which modulated microbial activity and presumably also fluroxypyr availability to microorganisms. Our findings imply that fluroxypyr may not be a suitable herbicide for weed control on railway tracks.

Published in

Journal of Environmental Quality
2012, Volume: 41, number: 6, pages: 1884-1892
Publisher: AMER SOC AGRONOMY

SLU Authors

• Cederlund, Harald

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

• Börjesson, Elisabet

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

• Thierfelder, Tomas

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Ensure availability and sustainable management of water and sanitation for all
Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Environmental Sciences


Publication identifier

DOI: https://doi.org/10.2134/jeq2012.0035

Permanent link to this page (URI)

https://res.slu.se/id/publ/40580