Characterization of organochloride pesticides residues in sediments from the Cienaga Grande of the lower Sinú river of Colombia

Abstract The levels of organochloride pesticides (OCPs) residues in sediment samples from four stations in the Cienaga Grande (swamp area) of the lower Sinú River in the Caribbean region and receiving run-offs from the Sinú River effluents in Córdoba, Colombia were investigated. Ninety-six composite samples of surface sediments covering a radius of 3 m were randomly collected using the “Van Veen” dredge technique and were subsequently analyzed for pesticide residues using a gas chromatograph equipped with an electron capture detector. A total of five OCPs residues, most of them persistent organic pollutants, were identified and quantified. Results showed that the concentrations of various pesticides in sediments were in the range of 2.85–7.05 ng/g for α-hexachlorocyclohexane (α-HCH), 0.26–2.31 ng/g for β-HCH, 0.59–7.57 ng/g for γ-HCH (lindane), 0.69–1.72 for aldrin, and 1.55–2.25 ng/g for heptachlor epoxide. Among the OCPs, the Σ-HCH (total positional isomers of HCH) was the dominant compounds in the Cienaga Grande sediments. The study concluded that most of the stations monitored in the Cienaga Grande areas were contaminated with OCPs associated with the accumulation of water run-off from surrounding areas arriving at the location during the winter time. This in turn implies that the increased pollution load is related to the discharge of wastewater and solid waste from various municipal centers and towns located about the Cienaga Grande.