Dissipation of glyphosate and aminomethylphosphonic acid in water and sediment of two Canadian prairie wetlands.

Glyphosate [N-(phosphonomethyl)glycine] is the active ingredient of several herbicide products first registered for use in 1974 under the tradename Roundup. The use of glyphosate-based herbicides has increased dramatically over the last two decades particularly in association with the adoption of glyphosate-tolerant crops. Glyphosate has been detected in a range of surface waters but this is the first study to monitor its fate in prairie wetlands situated in agricultural fields.

Dissipation of six acid herbicides in water and sediment of two Canadian prairie wetlands.

In the present study, an ephemeral (E) and a semipermanent (SP) wetland were divided into halves using a polyvinyl curtain and one-half of each wetland was treated with dicamba (3,6-dichloro-o-anisic acid), bromoxynil (3,5-dibromo-4-hydroxy-benzonitrile), MCPA [(4-chloro-2-methylphenoxy)acetic acid], 2,4-D [(2,4-dichlorophenoxy)acetic acid], mecoprop-P (R)-2-(4-chloro-o-tolyloxy)propionic acid], and dichlorprop [(RS)-2-(2,4-dichlorophenoxy)propionic acid] such that concentrations in the water simulated an overspraying event, thus representing a worst-case scenario for wetland contamination. Water and sediment samples were taken over the 77-d study period to monitor herbicide concentrations. The dissipation of all six herbicides could be described by first-order reaction kinetics.

Trace level determination of selected sulfonylurea herbicides in wetland sediment by liquid chromatography electrospray tandem mass spectrometry.

Sulfonylurea herbicides are widely used in crop production on the Canadian prairies and a portion of these herbicides applied to cropland are inevitably lost to surrounding aquatic ecosystems. Little is known regarding the presence of sulfonylurea herbicides in wetlands located amongst cropland. This paper describes a new analytical method for the extraction and the determination of seven sulfonylurea herbicides (thifensulfuron-methyl, tribenuron-methyl, ethametsulfuron-methyl, metsulfuron-methyl, rimsulfuron, nicosulfuron and sulfosulfuron) in wetland sediment.

Land use and riparian effects on prairie wetland sediment properties and herbicide sorption coefficients.

Sorption of commonly used herbicides by wetland sediment can provide important information for herbicide fate modeling. The influence of sediment properties on herbicide sorption as a result of different land uses in the wetland catchment is unclear. We examined the effects of land use on the physiochemical properties of wetland sediments and the associations between these sediment properties and herbicide sorption characteristics.