IMPACT OF ARTHROPOGENIC ACTIVITICS AND HEAVY-METALS ON THE DISTRIBUTION OF BENTHIC-FAUNA COMMUNITY IN OKERENKOKO

Abstract

Nigerian aquatic systems have been contaminated at various levels since the discovery of oil and gas. Heavy metals, physiochemical and benthic invertebrate community were investigated on the Okerenkoko estuary. Surface water samples and sediments were collected across five stations in the month of September and October between 08: 00 and 12: 00hrs. Water samples were analysed following established methods while sediments collected with grab were sieved, sorted and benthic organisms were preserved in 5% formalin. Heavy metals, (Cr, Cu, Hg, Zn, Cd, and Pb) were analysed using a Varian 220 (rapid sequential) Atomic Absorption Spectrometer (AAS). The ANOVA Output: indicates significant changes in heavy metals in sediment, with a p-value of (0.033). with a significant difference between TDS, pH, and EC with high p-values. Analysis of variance showed, no significant difference (p>0.05) as observed in the mean values of the physiochemical parameters across all stations, due to differences in physiochemical parameters and heavy metals in sediments. Linear regression analysis suggests a strong negative connection that as physiochemical factors grows, benthic-fauna is likely to decline. A total of 30 individuals comprising 6species, 5genera, 5families, 4orders, 3classes, and 2phyla. Members of the Phylum Mollusca constituted (88.2%) and (84.6%) in September and October, with Tympanotonus fuscatus var fuscatus being the dominant species, Phylum Arthropoda constituted (11.8%) and (15.4%) in September and October. The studies’ low species diversity patterns reflect, human activities (artisanal distilleries). The most Adaptive species, Tympanotonus fuscatus var fuscatus, was established. As to sensitive, Calllinectes similis and Penaeus monodon. This might indicate that Okerenkoko waterbody is progressively exposed to indiscriminate anthropogenic stress. The routine study and regular monitoring of the state of the waterbody be conducted and analysis of the dynamic interplay among components is necessary for sustainable water quality management.