title: Inhibition of cholinesterase activity by soil extracts and predicted environmental concentrations (PEC) to select relevant pesticides in polluted soils.
abstract: The correlation of predicted environmental concentrations (PEC) with cholinesterase activity inhibition detected in soil extracts was determined. PEC was derived from organophosphate (OP) and carbamate (CA) compounds applied to a flower crop area. Samples of surface soil (0 - 30 cm in depth) and subsurface soil (30 to 60 cm in depth) were taken from a flower crop area in which OP pesticides such as acephate ((RS)-N-[methoxy(methylthio)phosphinoyl]acetamide), dimethoate (2-dimethoxyphosphinothioylthio-N-methylacetamide) and methyl parathion (O,O-dimethyl O-4-nitrophenyl phosphorothioate), and CA pesticides such as carbendazim (methyl benzimidazol-2-ylcarbamate), carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) and methomyl (S-methyl (EZ)-N-(methylcarbamoyloxy) thioacetimidate) were applied for two years. Weekly loads of these pesticides were registered to estimate the annual load of each compound. Physicochemical analysis and relative inhibition of cholinesterasic activity were measured for each soil sample. PEC values were estimated with Pesticide Analytical Model (PESTAN), a leach model, for each pesticide using soil sample data obtained from physicochemical analysis. From all pesticides tested, only acephate and methomyl showed a significant correlation (p < 0.01) between PEC values and inhibition cholinesterase activity of soil extracts. These results suggest that inhibition of cholinesterase activity observed in soil extracts is produced mainly by these two pesticides. Further studies could be developed to measure acephate and methomyl concentrations to reduce their environmental impact.
authors.affiliation: Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Toluca, Mexico.
authors.forename: Juan C Sanchez
authors.initials: JC
authors.lastname: Meza
authors.forename: Pedro Avila
authors.initials: PA
authors.lastname: Perez
authors.forename: Manuel Borja
authors.initials: MB
authors.lastname: Salin
authors.forename: Victor F Pacheco
authors.initials: VF
authors.lastname: Salazar
authors.forename: Tom
authors.initials: T
authors.lastname: Lapoint
mesh_terms: D002800:Cholinesterase Inhibitors / Q000032:analysis*; D002802:Cholinesterases / Q000378:metabolism*; D004784:Environmental Monitoring; D008724:Methomyl / Q000032:analysis / Q000633:toxicity; D009946:Organothiophosphorus Compounds / Q000032:analysis / Q000633:toxicity; D010573:Pesticide Residues / Q000032:analysis* / Q000633:toxicity; D010575:Pesticides / Q000032:analysis* / Q000633:toxicity; D063088:Phosphoramides; D012989:Soil Pollutants / Q000032:analysis* / Q000633:toxicity
chemical_list: D002800:Cholinesterase Inhibitors; D009946:Organothiophosphorus Compounds; D010573:Pesticide Residues; D010575:Pesticides; D063088:Phosphoramides; D012989:Soil Pollutants; D008724:Methomyl; C001969:acephate; D002802:Cholinesterases