|Journal of Research in Environmental Science and Toxicology (ISSN: 2315-5698) Vol. 6(1) pp. 001-007, May 2017. DOI: http:/dx.doi.org/10.14303/jrest.2017.011. Copyright © 2017 International Research Journals
Full Length Research Paper
Residual levels of the organophosphate malathion in water, sediment and a threatened fish from Ethiope River, Delta State, Nigeria
1Erewa O. and 2Ikpesu T.O
1Department of Animal and Environmental Biology, University of Benin, Nigeria
2Department of Biological Sciences, Federal University Otuoke, Nigeria
Corresponding author’s E-mail: firstname.lastname@example.org
Received February 10, 2017; Accepted March 15, 2017
The organophosphate pesticide malathion, was observed and measured in water, sediment and fish (Tilapia mariae) from Ethiope River. This study was made from three stations, Amukpe, Igun watershed and Owah-Abe, all along the River during the dry (January-April) and wet seasons (May-August). The physicochemical and microbiological characteristics of surface water were also taken on a monthly basis. Analysis of the pesticide was done using High Performance Liquid Chromatography (HPLC model CECIL 1010) to elucidate its distribution in the different environmental compartments. The concentration of the pesticide residue in the matrices ranged from 0.01μg/l – 2.24μg/l (water), 0.03ug/gdw – 2.46ug/gdw (sediment) and 0.16ug/gdw – 5.10ug/gdw (Tilapia mariae) during the dry and wet seasons. Results from the study showed that sediment and Tilapia mariae were higher in malathion residue than water, that is, concentrations of malathion increased in the order of water, sediment, fish samples. Spatial variations occurred with downstream stations having statistically higher concentrations in all matrices at p < 0.05. There was seasonal variation with higher concentrations of malathion residues observed in the dry season for water, while sediment and fish had higher concentrations during the wet season. The physicochemical parameters analysed were within the recommended limit accepted by the regulatory body in Nigeria. The observed residual levels of malathion were above the ecological bench mark (0.01ug/l) stipulated by the Federal Ministry of Environment, an observation that calls for proper monitoring of the Niger Delta water bodies in Nigeria so as to prevent contamination that could be detrimental to human health.
Keywords: Surface water; Sediment; Ethiope River; Amukpe; Igun ; Owah Abe.