Trace metal pollution and its impacts on the macroinvertebrate community assemblage in a tropical reservoir

Abstract

AbstractThe extent of metal pollution in the sediment of Osinmo reservoir was determined with a view to assessing the impact of heavy metal concentrations on the community assemblage of the macroinvertebrates there‐in. The range of the mean concentrations of heavy metals are as follows: Pb (6.66–7.89 mg/kg), Cu (1.04–2.63 mg/kg), Mn (34.03–61.69 mg/kg), Zn (3.59–8.17 mg/kg) and Ni (0.08–0.1 mg/kg).The mean concentration of the investigated heavy metals in the reservoir sediment followed the order Mn > Pb > Zn > Cu > Ni. Insignificant variation of the heavy metals was observed amidst the three reaches of the reservoir except for Mn which showed a significant difference (p < 0.05). Although the insect groups were generally more sensitive to the sediment parameters than the noninsect group, the community assemblage was observed not to have been significantly impacted by these variations. The values obtained from enrichment analysis of the metals were generally lower than the background values and this indicated that a significant portion of the heavy metals in the sediment was derived from natural sources thus suggesting the existence of a stable ecological community in the Reservoir.