Table of Contents
ISRN Soil Science
Volume 2013 (2013), Article ID 131647, 12 pages
http://dx.doi.org/10.1155/2013/131647
Research Article

Organochlorine Pesticide Residues in Sediments and Waters from Cocoa Producing Areas of Ondo State, Southwestern Nigeria

1Institute of Ecology and Environmental Studies, Obafemi Awolowo University, Ile-Ife, Nigeria
2Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria
3Department of Chemistry, Rhodes University, Grahamstown 6140, South Africa

Received 10 January 2013; Accepted 5 February 2013

Academic Editors: D. Lin, C. Martius, and D. van Tuinen

Copyright © 2013 Aderonke Adetutu Okoya et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study investigated levels of organochlorine pesticide (OCP) residues in water and sediment samples from eleven rivers serving as drinking water sources and receiving runoff from nearby cocoa plantations in Ondo State, Nigeria. Twenty-two composite samples of surface water and sediments (0–3 cm) were collected randomly using grab technique and replicated thrice per season. The efficiency of the two techniques [supercritical fluid extraction (SFE) and liquid/liquid extraction (LLE)] was evaluated with percentage analyte recoveries to for SFE and to 1 for LLE. Determination of OCPs by gas chromatography with electron capture detection gave higher concentrations for sediments compared to the equivalent water samples. The commonly occurring pesticide residues in the sediments were (range, μg g−1) cis-chlordane 0.03–6.99; α-endosulfan 0.03–6.99; p,p′-DDE 0.08–19.04; and dieldrin 0.01–7.62; in the sediments and dieldrin (not detected-1.51 μg L−1) in water samples, during the dry season. OCP levels were significantly higher in dry season than wet season among the rivers. The study concluded that most of the rivers in cocoa growing areas were contaminated with OCPs associated with agricultural activities.