Assessment of Temporal Variation of Water Quality Parameters and Ecotoxic Trace Metals in Southern Nigeria Coastal Water

Abstract

This study investigated the temporal variations of water quality parameters and ecotoxic trace metal contamination in the Opuroama River over a year, with a focus on providing baseline data for regulating water and fisheries resources in the area. Metal concentrations in sediment, water, and four aquatic organisms were analyzed for cadmium (Cd), chromium (Cr), nickel (Ni), and lead (Pb) using atomic absorption spectrophotometry. Metal concentration in C. amnicola occurred in the order: Cr>Cd>Ni>Pb, U. tangeri: Cr>Pb>Cd>Ni, T. fuscatus: Cr>Pb>Ni>Cd, P. monodon: Pb>Cr>Ni>Cd, while in sediment, the order was Cr>Pb>Cd>Ni, and water occurred in the order: Cr>Pb>Ni>Cd. Results showed temporal variations in water physicochemical parameters, with Cd and Ni concentrations within 0.003 mg/L, and 0.02 mg/L reported as set standard limits for aquatic ecosystems except for Cd in December, which exceeded permissible limits. Pb concentrations were below the threshold of 0.01 mg/L from January to May but progressively increased and exceeded limits from June to December. Cd had the highest mean concentration in sediment and the least in water and aquatic organisms, while Ni had the highest mean concentration in U. tangeri and water and the lowest in T. fuscatus and P. monodon. Pb had the highest concentration in water and the lowest in C. amnicola, while U. tangeri had the highest mean Cr value. The study suggests potential health risks to humans and the environment from the presence of potentially toxic elements in the studied media.