title: [Pesticide residues in drinking water of an agricultural community in the state of Mérida, Venezuela].
abstract: The aim of this study was to determine the presence of pesticides in drinking water from six aqueducts in a region of intense agricultural activity in the state of Merida, Venezuela. The study was conducted for four continuous weeks, between May and June 2008. Pesticide residues were analyzed by solid phase extraction (SPE) and liquid chromatography (HPLC) with diode array detector (DAD). The method SPE-HPLC-DAD met the criteria of analytical validation, with good linearity (R2: 0.9840 to 0.9999), precision (coefficient of inter-day variability from 1.47 to 6.25%), accuracy (relative standard deviation 0.9 to 9.20%) and sensitivity (LOD < or = 0.012 microg/L; LOQ < or = 0.030 microg/L, except mancozeb with 0.400 microg/L). Seven of the thirteen selected pesticides have a recovery rate between 100% and 70%, the rest between 61% and 37%. Ten pesticides of the following chemical groups, were detected in 72 samples analyzed: organophosphates, carbamates, triazines and urea derivatives. The pesticides with the highest frequency of detection were: carbofuran and atrazine (39%), malathion (25%), dimethoate and metribuzin (19%). The pesticides found at high levels were diazinon (26.31 microg/L), methamidophos (10.99 microg/L), malathion (2.03 microg/L) and mancozeb (1.27 microg/L). Pesticide levels did not exceed the maximum allowed by Venezuelan law, however, according to international standards (EU and EPA-USA) values were above the maximum permissible levels. This study demonstrates the urgent need for systematic monitoring of the quality of water for human consumption in regions of high agricultural productivity.
authors.affiliation: Centro de Microscopía Electrónica "Dr Ernesto Palacios Prü", Universidad de Los Andes, Mérida, Venezuela.
authors.forename: Mery Elisa
authors.initials: ME
authors.lastname: Flores-García
authors.forename: Yuri
authors.initials: Y
authors.lastname: Molina-Morales
authors.forename: Alirio
authors.initials: A
authors.lastname: Balza-Quintero
authors.forename: Pedro Rafael
authors.initials: PR
authors.lastname: Benítez-Díaz
authors.forename: Leticia
authors.initials: L
authors.lastname: Miranda-Contreras
mesh_terms: D000383:Agriculture / Q000379:methods; D002219:Carbamates / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D008452:Maximum Allowable Concentration; D010755:Organophosphates / Q000032:analysis; D010573:Pesticide Residues / Q000032:analysis*; D012423:Rural Health; D012680:Sensitivity and Specificity; D014227:Triazines / Q000032:analysis; D014508:Urea / Q000032:analysis; D014687:Venezuela; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
chemical_list: D002219:Carbamates; D010755:Organophosphates; D010573:Pesticide Residues; D014227:Triazines; D014874:Water Pollutants, Chemical; D014508:Urea