title: Priority pesticides and their degradation products in river sediments from Portugal.
abstract: A multiresidue gas chromatography-mass spectrometry method was developed to determine 28 priority pesticides of different chemical families (organochlorine, organophosphorus, triazines, anilides) together with some of their transformation products in river sediment. Ultrasonic, Soxhlet and pressurized liquid extraction (PLE) methods were compared in spiking experiments using acetone:hexane (1:1) followed by alumina solid phase extraction cartridges or in-cell alumina clean-up for PLE. All extraction techniques produced acceptable recoveries for the pesticides under study, although Soxhlet extraction produced the lowest recoveries for 2,4-DDE, trifluralin, lindane, and hexachlorobenzene (<50%) whereas ultrasonic extraction resulted in low recoveries for hexachlorobenzene and lindane (<50%). However, PLE using in-cell alumina clean-up produced an overestimation of more apolar compounds, given the amount of coextracted compounds. Limits of detection at the low microg L(-1)-ng L(-1) levels were obtained with Soxhlet and ultrasonic extraction, while PLE produced higher variability due to the lack of exhaustive clean-up. Given the simplicity of ultrasonic extraction, this method was further employed to determine target compounds in river sediments collected in Portugal. Lindane was detected in practically all samples, followed by trace levels of the pesticides simazine, diazinon, fenitrothion, and parathion-methyl.
authors.affiliation: Instituto de Recursos Naturales y Agrobiología de Sevilla (CSIC), Apdo 1052, 41080-Sevilla, Spain. jvillaverde@irnase.csic.es
authors.forename: Jaime
authors.initials: J
authors.lastname: Villaverde
authors.forename: Alain
authors.initials: A
authors.lastname: Hildebrandt
authors.forename: Elena
authors.initials: E
authors.lastname: Martínez
authors.forename: Sílvia
authors.initials: S
authors.lastname: Lacorte
authors.forename: Esmeralda
authors.initials: E
authors.lastname: Morillo
authors.forename: Celia
authors.initials: C
authors.lastname: Maqueda
authors.forename: Paula
authors.initials: P
authors.lastname: Viana
authors.forename: Damià
authors.initials: D
authors.lastname: Barceló
mesh_terms: D004784:Environmental Monitoring / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000737:chemistry*; D010575:Pesticides / Q000032:analysis / Q000737:chemistry*; D011174:Portugal; D045483:Rivers; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D010575:Pesticides; D014874:Water Pollutants, Chemical