title: The fate of isoproturon in a freshwater microcosm with Lemna minor as a model organism.
abstract: Degradation, bioaccumulation and volatile loss of the 14C-labeled phenylurea herbicide isoproturon (IPU) was examined in a freshwater microcosm with the free floating macrophyte species Lemna minor during a 21-day exposure time. Isoproturon volatilisation was very low with 0.13+/-0.01% of the initially applied herbicide. Only a minor amount of the herbicide was completely metabolised, presumably by rhizosphere microorganisms and released as 14CO2. In total, about 9% isoproturon was removed from the aquatic medium during 21 days. The major portion of the pesticide was removed by bioaccumulation of Lemna minor (5.0+/-0.8%) and the bioconcentration factor (BCF) based on freshweight was 15.8+/-0.2. However, this study indicated a high persistence of IPU in freshwater ecosystems and a potential hazard due to bioaccumulation in non-target species. The novel experimental system of this study, developed for easy use and multiple sampling abilities, enabled quantitatively studying the fate of isoproturon and showed high reproducibility with a mean average (14)C-recovery rate of 97.1+/-0.7%.
authors.affiliation: Institute of Soil Ecology, GSF-National Research Center for Environment and Health, Neuherberg, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Böttcher
authors.forename: Reiner
authors.initials: R
authors.lastname: Schroll
mesh_terms: D005618:Fresh Water; D006540:Herbicides / Q000493:pharmacokinetics*; D010671:Phenylurea Compounds / Q000493:pharmacokinetics*; D063245:Plant Development; D010944:Plants / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics*
chemical_list: D006540:Herbicides; D010671:Phenylurea Compounds; D014874:Water Pollutants, Chemical; C028904:isoproturon