African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6576

Full Length Research Paper

Organochlorine (OC) pesticide residues in soils of major cocoa plantations in Ondo State, Southwestern Nigeria

A. A. Okoya1*, N. Torto2, A. O. Ogunfowokan3 and O. I. Asubiojo3
1Institute of Ecology and Environmental Studies, Obafemi Awolowo University, Ile-Ife, Ondo State, Nigeria. 2Department of Chemistry, Rhodes Uniiversity, Grahamstown 6140, South Africa. 3Department of Chemistry, Obafemi Awolowo University, Ile – Ife, Ondo State, Nigeria.  
Email: [email protected], [email protected]

  •  Accepted: 25 July 2013
  •  Published: 26 July 2013


Organochlorine compounds were extracted from soils of major cocoa plantations in Ondo State of Nigeria by supercritical fluid extraction and their concentrations were determined by electron capture detector – gas chromatography. The percentage recoveries for the optimized extraction temperatures were 89.99 ± 0.05 to 105.24 ± 0.04 at 60°C and 63.88 ± 1.12 to 93.33 ± 0.15 at 80°C while the analytes were not detected at 50 and 100°C. The extraction pressure was also optimized and percentage recoveries were 54.13 ± 5.03 to 87.98 ± 10.56 and 89.99 ± 0.05 to 105.24 ± 0.04 at 200 and 300 Bar, respectively. Results of routine analysis using the optimized conditions (60°C, 300 Bar) showed that soils of the study area are contaminated by organochlorine compounds (OCCs) in varied degree which ranged from ND to 40.55 ±1.54 µg/g which may be due to pesticide application on cocoa plantations for the control of insect pests and diseases in the study area.


Key words: Organochlorine pesticides (OCPs), soil, supercritical fluid extraction, electron capture detector – gas chromatography (ECD-GC).