Spatial variability of heavy metal bioaccumulation in tilapia (Tilapia guineensis) and its correlation with water and sediment quality in River State

Abstract

This study examines the spatial variability of heavy metal bioaccumulation in Tilapia guineensis and its correlation with water and sediment quality across Akuku Toru, Asari Toru, and Degema in Rivers State, Nigeria. Heavy metals such as cadmium (Cd), lead (Pb), chromium (Cr), arsenic (As), zinc (Zn), copper (Cu), and nickel (Ni) were analyzed in water, sediment, and fish samples collected from the region. Results indicate significant variations in heavy metal concentrations across stations. Asari Toru recorded the highest cadmium concentration in fish (0.027 mg/kg), while Degema had the highest lead (0.05 mg/kg) and chromium (0.052 mg/kg) concentrations. The bio-sedimentation factor (BSF) showed that arsenic had the highest bioaccumulation in tilapia, with BSF values ranging from 0.182 to 0.700 across stations. Furthermore, the bioaccumulation factor (BAF) demonstrated considerable arsenic bioaccumulation in fish tissues, with values ranging from 0.366 to 2.333. Copper and zinc were two other metals with minor bioaccumulation. This study’s findings also suggest a correlation between heavy metal levels in water and sediments and the bioaccumulation of heavy metals by fish. Although most metal concentrations are under regulatory limits, the potential health risks associated with long-term heavy metal ingestion from fish diets raise concerns, particularly in sensitive regions.The findings emphasise the need of ongoing monitoring and stricter environmental regulations in reducing the risks posed by heavy metal contamination in the Niger Delta's aquatic environment.