Showing papers by "Jean-Michel Portal published in 2006"
TL;DR: Electrophoretic measurements and steady-state fluorescence spectroscopy with pyrene revealed that the interaction of Al(13) coagulant species with MHS functional groups induces the formation of intramolecular hydrophobic microenvironments.
81 citations
TL;DR: In this article, the degradation half-life of extractable isoproturon was an estimated 14 days, and 72% of the radiolabel added remained in the soil as non-extractable residue.
Abstract: Resume
La disponibilite et la degradation de l'isoproturon dans le sol au cours du temps ont eteevaluees pendant 140 jours dans une experience de laboratoire en conditions controlees a l'aide de la molecule marquee au 14C sur le cycle. L'etat de degradation de la matiere active a ete suivi: apres 65 jours, l'isoproturon extractible ne represente plus qu'une tres faible part (0,6%). Le monodemethyl-isoproturon est mesurable des le 15eme jour (2,6%). La mesure du 14CO2 provenant de la degradation du cycle benzenique et degage au cours du temps donne un total de 13,6% d'isoproturon mineralises durant l'incubation. Parallelement, les quantites de residus extractibles (par l'eau puis par le methanol) ou subsistant dans le sol quelle que soit leur forme (dosage par combustion) ont ete successivement mesurees. Apres 140 jours, 72% de la radioactivite apportee se trouve sous forme non extractible dans le sol. La demi-vie de la matiere active isoproturon extractible est estimee a 14 jours.
Summary
Degradation if isoproturon and availability of residues in soil
The availability and degradation of 14C-ring-labelled isoproturon in soil was investigated over 140 days under controlled laboratory conditions. Degradation of the active ingredient followed and 65 days later only a minor fraction (0.6%) of the parent molecule remained extractable. A demethylated-isoproturon metabolite was detectable in soil from day 15 (2.6%). The amount of 14CO2 derived from the 14C benzene ring label and liberated over time indicated that a total of 13.6% isoproturon was mineralized during the incubation period. In parallel, the amount of 14C residue extracted from the soil by water followed by methanol or remaining within the soil—analysed by combustion—was also determined at intervals. After 140 days, 72% of the radiolabel added remained in the soil as non-extractable residue. The degradation half-life of extractable isoproturon was an estimated 14 days.
9 citations