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.

Keywords:

• organochloride pesticides
• persistent organic pollutants
• gas chromatography
• swamp sediments
• Cienaga Grande of the Sinú River of Colombia

Public Interest Statement

Concentrations of five organochloride pesticide (OCP) residues, α-hexachlorocyclohexane (α-HCH), β-HCH, γ-HCH, aldrin and heptachlor epoxide, most of them persistent organic pollutants (POPs), were identified and quantified in sediment samples from four stations on the Cienaga Grande (swamp area) in the lower Sinú River of the Caribbean Colombia region, an approximate area of 791 km² and receiving runoffs from Sinú River effluents on Cordoba. Results showed that among the OCPs detected, Σ-HCH (total HCH) was the most dominant and widely distributed compound in the sediments. It was also found that most of the stations monitored were contaminated with OCPs, mainly due to intense agricultural activity and slow degradation rates associated with the accumulation of water runoff from surrounding areas arriving. This study will provide a database to government authorities with the perspective to develop monitoring programs that will help minimize the risk of human exposure to organochloride pesticides.

Competing interests

The authors declare no competing interest

Additional information

Notes on contributors

Samuel P. Hernández-Rivera

Samuel P. Hernández-Rivera, PhD, is a professor of Physical Chemistry at the Chemistry Department of the University of Puerto Rico-Mayagüez Campus (UPRM). He is the director of the DoD-MURI sponsored Center for Chemical Sensors Development and the UPRM-based Chemical Imaging annd Surface Analysis Center and the UPRM Principal Investigator of the DHS ALERT Center of Excellence for Explosives Research. He also directs the DOD sponsored Chemical Imaging and Surface Analysis Center. He obtained his BS and MS degrees from UPRM and PhD from the Johns Hopkins University. His research interests are in IR/Raman spectroscopies in applied and fundamental studies and in stand-off and point detection of explosives, chemical and biological agents and other hazardous compounds using vibrational spectroscopy. Other interests are: environmental chemistry, SERS and in chemometrics enhancement of spectroscopic data and discriminant and cluster analysis of populations.