Pesticide residues in river sediments from the Pantanal Wetland, Brazil

Abstract

Sediment samples from 25 sites in 17 rivers of the Pantanal (Brazil) were analyzed with the objective of evaluating pesticide contamination in sediments. Samples were extracted with an acetone, ethylacetate, and water mixture 2:2:1 (v/v/v). The extract was purified by flash chromatography with aluminum oxide and florisil. A multiresidue gas chromatography-mass spectrometry method was applied to monitor 23 pesticides of different chemical classes (organochlorine, organophosphorus, triazines, anilides and pyrethroids) with some of their degradation products. Compounds identified in sediment samples included λ -cyhalothrin (1.0 to 5.0 μ g kg^{− 1}), p,p′-DDT (3.6 μ g kg^{− 1}), deltamethrin (20.0 μ g kg^{− 1}) and permethrin (1.0 to 7.0 μ g kg^{− 1}).

Keywords:

• Pesticide
• sediment
• gas chromatography
• Pantanal

Acknowledgments

This research was part of the Projeto Ecológio de Longa Duração (PELD) program (Ecological projects of long duration), supported by the Brazilian CNPq and the Brazilian Instituto Brasileiro de Meio Ambiente e dos Recursos Naturais (IBAMA). The authors thank Prof. Dr. E. R. Pereira-Filho for reviewing an earlier version of the manuscript.

Notes

^(a)F, fungicide; H, herbicide; I, insecticide.

^(b)Ions used for substance quantification (first ion) and identification (second and third ions) during the selected ion monitoring (SIM).

^(c)Spike of 0.1 mg kg^{− 1} sediment (n = 3), samples of 25 g sediment dry mass.

^(d)Samples of 25 g of sediment dry mass.