ABSTRACT

The sediment characterization and evaluation of benthic macroinvertebrates of Selected Ponds in Ogharra, Delta State, Nigeria was carried out for three (3) months across three (3) stations from January 2021 through March, 2021. To determine the heavy metals, sediment characteristics, specie composition and relative abundance of the benthic macro invertebrate. Samples were collected using an Ekman grab from the sediment, benthic macro invertebrate  was sorted using a magnifying lens and was preserved with 4% formalin. The heavy metals of the sediment were analyzed and studied and they include, Iron (Fe) (480.50 – 1224.47 mg/kg), Copper (Cu) (8.76– 17.80 mg/kg), Manganese (Mn) (7.10 – 14.00 mg/kg), Lead (Pb) (0.47 – 2.29 mg/kg), Chromium (Cr) (0.18 – 2.63 mg/kg), and Zinc (Zn) (7.63 – 14.00 mg/kg) and also the Particle size distribution and Organic content (% organic carbon and % organic matter) were also analyzed. Heavy metals apart from iron parameters were within the allowable limits of USEPA for fresh water bodies. A total of 16 taxa comprising of 182 individuals were recorded during the study. Hemiptera accounted for 6%, Coleoptera accounted for 15%, Odonata accounted for 10%, Diptera accounted for 53%, Ephemeroptera accounted for 7%, Mollusca accounted for 3%. The total number of taxa in station 1 were 7 with 47 total number of individuals. In station 2, 14 taxa were recorded and individuals were 78 while in station 3, the total number of taxa and individuals were 12 and 57 respectively. Shannon Weiner’s index was used to calculate general diversity and showed that Station 3 had the highest diversity. From the coefficient correlation analysis, it was observed that the distribution and abundance of some benthic macroinvertebrates by changes in some physico-chemical parameters. Factors which influenced the abundance and distribution of the benthic macroinvertebrates includes the nature of the water body, habitat richness and stability, immediate substrate of occupation, the heavy metal composition, anthropogenic activities, tropic condition, resource partitioning and predation.