title: Influence of usage and chemical-physical properties on the atmospheric transport and deposition of pesticides to agricultural regions of Manitoba, Canada.
abstract: This study quantified the masses of 14 pesticides deposited as wet (precipitation) versus dry (gaseous and particle) atmospheric deposition at a research farm in southwestern Manitoba, Canada. The concentration in air of these pesticides was also measured. Total bulk deposition amounts (wet+dry) ranged from 0.009 to 2.3 μg m(-2) for the 12 pesticides detected, and for the six pesticides with both wet and dry deposition detections, dry deposition contributed 12-51% of the total deposition over the crop growing season. Although not applied at the site, eight herbicides registered for use in Canada, as well as lindane (γ-HCH), were all frequently detected (92-100%) in the 12 air samples analyzed during the crop growing season, with by-product isomer α-HCH (75%), clopyralid (50%) and atrazine (8%) detected to a lesser extent. The chemical's physicochemical properties and the relative mean mass of each agricultural pesticide applied in the province of Manitoba and in a 13 km radius were significant parameters in explaining the trends in the concentrations of pesticides detected in our samples. The important contribution of dry deposition to total pesticide deposition warrants greater attention in arid and semi-arid areas such as the Prairie Region of Canada, also because under a changing climate this region is estimated to experience more severe droughts while the more favorable conditions predicted for pest infestations could lead to increased pesticide applications in agricultural and urban areas.
authors.affiliation: Department of Soil Science, Faculty of Agricultural & Food Sciences, University of Manitoba, 362 Ellis Building, Winnipeg, MB, Canada R3T 2N2. Paul@Messing.ca
authors.forename: Paul
authors.initials: P
authors.lastname: Messing
authors.forename: Annemieke
authors.initials: A
authors.lastname: Farenhorst
authors.forename: Don
authors.initials: D
authors.lastname: Waite
authors.forename: Jim
authors.initials: J
authors.lastname: Sproull
mesh_terms: D000383:Agriculture / Q000706:statistics & numerical data*; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data*; D001272:Atmosphere / Q000737:chemistry; D004784:Environmental Monitoring; D008350:Manitoba; D010575:Pesticides / Q000032:analysis*; D011891:Rain / Q000737:chemistry; D012621:Seasons
chemical_list: D000393:Air Pollutants; D010575:Pesticides