Anthropogenic Activities and the Quality of Aquatic Habitat with Reference to Heptachlor in Ethiope River Basin

The influences of man on the quality of aquatic habitat is indispensable, hence the distribution of heptachlor, one of the most sought pesticide in the nascent fragile Niger- Delta environment in the water, bottom sediment and Tilapia mariae in Ethiope River Basin was investigated. Samples were collected monthly from three stations, Amukpe, Igun watershed and Owah-Abe, all along the River during the dry (January-April) and wet seasons (May-August).These stations were chosen because of their close proximity to where the pesticide is regularly use except the control station. The concentration of the pesticide was analyzed using CECIL 1010 model of high performance liquid chromatography. The results revealed a higher concentration of the pesticide in surface water during the dry season, than the wet season while the reverse was the case for the bottom sediment and T. mariae which had higher concentrations during the rainy season. Spatial variations showed that the downstream stations had statistically higher concentrations in all matrices at p < 0.05. The observed concentrations of heptachlor were above the permissible limits set by Nigeria National Environment Standards and Regulation Enforcement Agency for aquatic water bodies (0.3 μg/gdw). Though, fishes and the likes may live freely in water contaminated with heptachlor, for a very long time with no health effects. However, pesticides can easily biomagnified along the trophic level, and the risk to aquatic species become greater when repeated applications occur, resulting in continual exposure to peak concentrations.

Author(s): Ikpesu TO, Erewa O and Anyiam IV