Comparison of annual dry and wet deposition fluxes of selected pesticides in Strasbourg, France Nathalie Sauret a, 1 , Henri Wortham a, * , Rafal Strekowski a , Pierre Hercke `s b , Laura Ines Nieto a a Marseilles University, Laboratoire Chimie Provence – UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo,13331 Marseilles Cedex 03, France b Arizona State University, Department of Chemistry and Biochemistry, Tempe, AZ 85287-1604, USA A modified one-dimensional cloud water deposition model is used to estimate the deposition fluxes of pesticides in the particle phase and compare the relative importance of dry and wet depositions. article info Article history: Received 3 April 2008 Received in revised form 19 June 2008 Accepted 22 June 2008 Keywords: Pesticides Wet deposition Dry deposition Model development for dry deposition abstract This work summarizes the results of a study of atmospheric wet and dry deposition fluxes of De- isopropyl-atrazine (DEA), Desethyl-atrazine (DET), Atrazine, Terbuthylazine, Alachlor, Metolachlor, Di- flufenican, Fenoxaprop-p-ethyl, Iprodione, Isoproturon and Cymoxanil pesticides conducted in Strasbourg, France, from August 2000 through August 2001. The primary objective of this work was to calculate the total atmospheric pesticide deposition fluxes induced by atmospheric particles. To do this, a modified one-dimensional cloud water deposition model was used. All precipitation and deposition samples were collected at an urban forested park environment setting away from any direct point pesticide sources. The obtained deposition fluxes induced by atmospheric particles over a forested area showed that the dry deposition flux strongly contributes to the total deposition flux. The dry particle deposition fluxes are shown to contribute from 4% (DET) to 60% (cymoxanil) to the total deposition flux (wet þ dry). Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction Ubiquitous in today’s farming culture, pesticides are used to protect the crops against weeds (herbicides), fungal parasites (fungicides), insects (insecticides) and slugs and snails (mollusci- cides). Not surprisingly, the current agricultural practice is con- sidered to be the main source of atmospheric pesticide pollution (Samsonov et al., 1998; Scholtz et al., 2002). Other important sources of pesticide pollution include production and industrial and urban applications. Globally, about 2.5 million tons of pesti- cides are sprayed onto cultivated land per year (Bergstrom and Stenstrom, 1998; Centner, 1998). In the late 1990s, about 500 10 6 kg of pesticides were sprayed annually in Europe (Candela, 2003). This corresponds to an average pesticide dose of 4.4 kg ha 1 (Candela, 2003). In France, about 19 million hectares of crops are sprayed annually with pesticides, i.e. 35% of the total surface area of France. Once sprayed over the desired area, pesticides may then enter the atmosphere via direct volatilization at the moment of their appli- cation or volatilize later from the ground surface or vegetation. The volatilized pesticides may then undergo further volatilization/ sublimation or be adsorbed on particle surfaces (Glotfelty et al., 1989). This ‘post-application’ volatilization represents a secondary source of pesticide pollution that can last for a relatively long time. For example, about 80–90% of certain pesticides can be lost to volatilization over several days (Glotfelty et al., 1984; Majewski et al., 1993; Taylor et al., 1976). Once airborne, pesticides are mixed within the boundary-layer where their atmospheric fate is mostly determined by given meteorological conditions (Van Pul et al., 1999). However, once the pesticides enter the free troposphere their atmospheric residence time is considerably prolonged and then may be transported over great distances on the global scale including the polar regions (Buser, 1990; Rawn et al., 1999a,b; Waite et al., 1995; Wania and Mackay, 1996). Once in the atmosphere, pesticides are partitioned among the gas, solid (particles) and liquid phases depending on their physical and chemical properties and the environmental conditions (Tsal and Cohen, 1991). Primary physical/chemical properties of the selected pesticides are shown in Table 1 (Sauret, 2002). The choice of pesticides and metabolites used in this work and shown in Table 1 is based on their different physico-chemical properties to better identify key factors that characterize the pesticide’s atmospheric behavior and fate. The understanding of the partition among the three phases is essential to model and predict the atmospheric transport and the environ- mental fate of pesticides. * Corresponding author. Tel.: þ33 4 91 10 62 44; fax: þ33 4 9110 63 77. E-mail address: Henri.Wortham@univ-provence.fr (H. Wortham). 1 Present address: University of Nice Sophia-Antipolis, Laboratoire de Radio- chimie, Sciences Analytiques et Environnement (LRSAE), Parc Valrose, 06108 Nice, France. Contents lists available at ScienceDirect Environmental Pollution journal homepage: www.elsevier.com/locate/envpol 0269-7491/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2008.06.034 Environmental Pollution 157 (2009) 303–312