Heavy Metals Assessment of Water, Sediments, and Some commercial Fish species of Lavun Flood Plain, Niger State, Nigeria

Abstract

Heavy metals are persistent pollutants that pose significant risks to aquatic ecosystems and human health due to their toxicity and ability to bioaccumulate. This study assessed the concentration of heavy metals (Lead, Cadmium, Cobalt, Nickel, Chromium, and Copper) in water, sediments, and commercially important fish species within the Lavun Flood Plain, Niger State, Nigeria. Samples were collected monthly over an eight-month period across four stations: Nku, Sa’achi, Nupeko, and Egagi. Analysis was performed using Atomic Absorption Spectrophotometer (AAS) following standard digestion procedures. Results show heavy metal concentrations varied across the environmental matrices. In water, Chromium recorded the highest mean value (0.40 ± 0.11 mg/L at Sa’achi), while Lead and Copper levels showed no significant differences across stations (p>0.05). Analysis revealed significantly higher metal loads compared to water, with Chromium reaching 7.29 ± 1.16 mg/L at Nku. Among the six fish species studied, Malapterurus electricus generally exhibited the highest bioaccumulation of metals including Lead (0.18 ± 0.24 mg/kg) and Nickel (2.48 ± 1.78 mg/L), while Oreochromis niloticus and Heterotis niloticus often recorded the lowest levels. The presence of these metals is largely attributed to anthropogenic activities such as agricultural runoff, domestic waste discharge, and the use of fertilizers and pesticides in the surrounding flood plain. These findings highlight the necessity of regular ecological monitoring to manage the risks posed to local consumers and the long-term health of the Lavun freshwater ecosystem.