title: Sorption of selected pesticides on soils, sediment and straw from a constructed agricultural drainage ditch or pond.
abstract: Buffer zones such as ponds and ditches are used to reduce field-scale losses of pesticides from subsurface drainage waters to surface waters. The objective of this study was to assess the efficiency of these buffer zones, in particular constructed wetlands, focusing specifically on sorption processes. We modelled the sorption processes of three herbicides [2-methyl-4-chlorophenoxyacetic acid (2,4-MCPA), isoproturon and napropamide] and three fungicides (boscalid, prochloraz and tebuconazole) on four substrates (two soils, sediment and straw) commonly found in a pond and ditch in Lorraine (France). A wide range of Freundlich coefficient (K fads) values was obtained, from 0.74 to 442.63 mg(1 - n) L (n) kg(-1), and the corresponding K foc values ranged from 56 to 3,725 mg(1 - n) L (n) kg(-1). Based on potential retention, the substrates may be classified as straw >> sediments > soils. These results show the importance of organic carbon content and nature in the process of sorption. Similarly, the studied pesticides could be classified according to their adsorption capacity as follows: prochloraz >> tebuconazole-boscalid > napropamide >> MCPA-isoproturon. This classification is strongly influenced by the physico-chemical properties of pesticides, especially solubility and K oc. Straw exhibited the largest quantity of non-desorbable pesticide residues, from 12.1 to 224.2 mg/L for all pesticides. The presence of plants could increase soil-sediment sorption capacity. Thus, establishment and maintenance of plants and straw filters should be promoted to optimise sorption processes and the efficiency of ponds and ditches in reducing surface water pollution.
authors.affiliation: LIEC, UMR 7360 CNRS, Université de Lorraine, BP 70239, 54506, Vandoeuvre-lès-Nancy, France, romain.vallee@univ-lorraine.fr.
authors.forename: Romain
authors.initials: R
authors.lastname: Vallée
authors.forename: Sylvie
authors.initials: S
authors.lastname: Dousset
authors.forename: David
authors.initials: D
authors.lastname: Billet
authors.forename: Marc
authors.initials: M
authors.lastname: Benoit
mesh_terms: D000327:Adsorption; D000383:Agriculture; D004777:Environment; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005602:France; D008956:Models, Chemical; D010575:Pesticides / Q000032:analysis / Q000737:chemistry*; D061005:Ponds / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D053833:Wetlands
chemical_list: D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical