title: Leaching of Diuron, Linuron and their main metabolites in undisturbed field lysimeters.
abstract: The increasing use of pesticides in Morocco raises the potential risk of groundwater contamination, notably in the Gharb area, which has a shallow groundwater table. Thus, the leaching of two phenyl-ureas, diuron and linuron and their metabolites through undisturbed soil columns was studied under outdoor conditions. The soil chosen is a loamy clay soil, representative of the Gharb agricultural area. After four irrigation events were applied from 31/03/2005 to 15/05/2005, leachates contained higher amounts of linuron (from 0.08% to 6.96% of applied linuron) than diuron (from 0% to 0.27%). The greater mobility of linuron might be related to its higher water solubility (64 mg x L(- 1) compared with 42 mg x L(- 1) for diuron) and smaller adsorption coefficient (K(oc) of 400 L x kg(- 1), compared with 480 L x kg(- 1) for diuron). Concerning their metabolites, greater amounts of, N'-(3,4-dichlorophenyl)-N, (DCPMU) than N'-3,4-dichlorophenylurea (DCPU) were detected N-dimethylurea in the percolates, from 0% to 0.046% and from 0% to 0.008%, respectively. At the end of the monitoring period, more linuron residues than diuron residues were recovered in the soil profiles, 25.02% and 16.41%, respectively. The diuron residues were found mainly in the 0-20 cm soil layer, whereas linuron residues reached the 20-40 cm soil layer. Under such experimental conditions, linuron leaching, and thus its potential to contaminate groundwater, is greater than that of diuron.
authors.affiliation: Faculté des Sciences-Ain Chock, Université Hassan II, Maarif Casablanca, Morocco. elimacheahde@yahoo.fr
authors.forename: Ahde
authors.initials: A
authors.lastname: El Imache
authors.forename: Abdelmalek
authors.initials: A
authors.lastname: Dahchour
authors.forename: Btissam
authors.initials: B
authors.lastname: Elamrani
authors.forename: Sylvie
authors.initials: S
authors.lastname: Dousset
authors.forename: Fironzo
authors.initials: F
authors.lastname: Pozzonni
authors.forename: Lucia
authors.initials: L
authors.lastname: Guzzella
mesh_terms: D000327:Adsorption; D000383:Agriculture; D004237:Diuron / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D008044:Linuron / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D008782:Methylurea Compounds / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D009018:Morocco; D010575:Pesticides / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D010671:Phenylurea Compounds / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D012995:Solubility; D014867:Water / Q000737:chemistry; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D008782:Methylurea Compounds; D010575:Pesticides; D010671:Phenylurea Compounds; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D008044:Linuron; D014867:Water; D004237:Diuron