title: Estimating half-lives of pesticides in/on vegetation for use in multimedia fate and exposure models.
abstract: Degradation half-lives in/on vegetation are needed in environmental risk assessment of pesticides, but these data are often not available for most active ingredients. To address this, we first correlated experimental soil degradation half-life data of 41 pesticides obtained from the reviewed literature with the corresponding experimental half-lives on plant surface. Degradation half-lives in soil were found to be four times slower compared with half-lives on plant surfaces. In a second step, we explored measured plant surface half-lives directly with those in vegetation. The results were validated by comparing computed values with results obtained from an experimental set-up. The uptake and dissipation of alpha-cypermethrin (insecticide) and bromopropylate (acaricide) was studied by detecting pesticide residues in whole and peeled tomato fruits using gas chromatography. Half-lives within vegetation were found to be four times faster compared with plant surface half-lives. Using this experimental based approach, it is concluded that the estimation of degradation half-lives of pesticides in/on vegetation to be used as input data in environmental mass balance models can be directly correlated from the more abundant ready experimental degradation half-life data for soil.
authors.affiliation: Department of Chemical Engineering, ETSEQ, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain. ronnie.juraske@urv.cat
authors.forename: Ronnie
authors.initials: R
authors.lastname: Juraske
authors.forename: Assumpció
authors.initials: A
authors.lastname: Antón
authors.forename: Francesc
authors.initials: F
authors.lastname: Castells
mesh_terms: D001561:Benzilates / Q000378:metabolism*; D005638:Fruit / Q000378:metabolism; D006207:Half-Life; D018551:Solanum lycopersicum / Q000378:metabolism*; D008954:Models, Biological; D010573:Pesticide Residues / Q000378:metabolism*; D011722:Pyrethrins / Q000378:metabolism*
chemical_list: D001561:Benzilates; D010573:Pesticide Residues; D011722:Pyrethrins; C017160:cypermethrin; C038267:isopropyl 4,4'-dibromobenzilate