title: Changes in the persistence of two phenylurea herbicides in two Mediterranean soils under irrigation with low- and high-quality water: A laboratory approach.
abstract: The disappearance of two phenylurea herbicides, chlorotoluron (CHL) and isoproturon (IPU), in two Mediterranean soils, an agricultural calcareous soil (S5) and an organic forest soil (S2), was assessed under irrigation with high- and low-quality water. Irrigation with wastewater, as opposed to irrigation with high-quality water, increased the degradation rate of both herbicides in both soils. For each soil, the decay rate of IPU was always higher than that of CHL, and both pesticides disappeared more rapidly from S5 with lower clay and organic carbon content than from S2. The degradation rate was inversely related with pesticide sorption on soil, because increased sorption would reduce pesticide bioavailability for decomposition. In most cases the residual concentration in soil of both phenylurea herbicides was better fitted to a bi-exponential decay model than to first-order or first-order with plateau models. Dehydrogenase activity, used as an indication of microbial activity, was very high in S2 in comparison with S5, but was not related to pesticide disappearance.
authors: Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Avda. de las Palmeras, 4, E-18100 Armilla, Granada, Spain; Département de Chimie, Faculté des Sciences, Université Abdelmalek Essaadi, B.P. 2121, M'hannech II, 93002 Tétouan, Morocco.
authors: Siham
authors: S
authors: ElGouzi
authors: Département de Chimie, Faculté des Sciences, Université Abdelmalek Essaadi, B.P. 2121, M'hannech II, 93002 Tétouan, Morocco.
authors: Khalid
authors: K
authors: Draoui
authors: Département de Chimie, Faculté des Sciences, Université Abdelmalek Essaadi, B.P. 2121, M'hannech II, 93002 Tétouan, Morocco.
authors: E H
authors: EH
authors: Chtoun
authors: Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Avda. de las Palmeras, 4, E-18100 Armilla, Granada, Spain.
authors: M
authors: M
authors: Dolores Mingorance
authors: Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Avda. de las Palmeras, 4, E-18100 Armilla, Granada, Spain. Electronic address: aranchaph@iact.ugr-csic.es.
authors: Aránzazu
authors: A
authors: Peña
mesh_terms: D057914:Agricultural Irrigation; D004784:Environmental Monitoring; D006540:Herbicides / Q000032:analysis*; D019083:Mediterranean Region; D008956:Models, Chemical; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D006540:Herbicides; D012987:Soil; D012989:Soil Pollutants
keywords: Dissipation; Kinetic models; Pesticides; Wastewater