Heavy Metals and Physicochemical Parameters Evaluation in the Upper Reaches of Bonny River, Niger Delta, Nigeria

Abstract

The objectives of the study were to determine distribution of heavy metal contamination in water, sediments and biota (Callinectes amniciola) of the upper reaches of the Bonny Estuary and to determine the impact on physicochemical characteristics of the water body. Sampled was from January to June 2020. The physicochemical parameters of the water varied slightly across the months but were within FEPA/WHO (2003) acceptable limits. Furthermore; the study compared the seasonal variations and determination of Bio-accumulation Factor (BF) of C. amnicola with respect to sediment. The study site is a tidal creek that drains into the main Bonny River channel within Niger Delta, Nigeria. The sampled locations/stations include Trans-Amadi slaughter in Azuabie {N4°81'49.9 and E7°04'63.4}, Okpoka Creek in Abuloma {N4°78'02.43 and E7°06'66.12} and Okirika Jetty {N4°73'70.04 and E7°09'56.93}. Samples of surface water, sediments and swimming crabs were collected from three different stations which were at least 1000 meters apart. The results of this study show that concentrations of the heavy metals (Fe and Zn) were both higher in the three media than the approved limits prescribed by the local regulatory authority. Although Cu was relatively within acceptable limit in the three media.
There is therefore the need to control the anthropogenic activities within or around the river. This will help to prevent effluent and solid waste discharges that lead to increase in the concentration of heavy metals in the aquatic environment. Routine monitoring should be encouraged to identify the major sources of heavy metals introduction into the river and their impacts on the aquatic resources.