Assessing the Levels of Heavy Metal Concentrations in the Water and Fish Species Linked to Potential Risks to Health in Olooge Lagoon, Lagos State

This study was conducted on Olooge Lagoon, to assess the concentration of heavy metals in water and three fish species (Tilapia, Silver Catfish, and Chinos), as well as to analyze the physicochemical parameters in the water samples collected. The objective of the study was to determine the concentrations of various heavy metals and evaluate potential health risks associated with fish consumption from the lagoon using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Health risk assessments (HRA) were conducted using Hazard Quotient (HQ), Hazard Index (HI), and Cancer Risk Index (CRI) models. The waters physicochemical parameters, including pH, TDS, and electrical conductivity, showed that alkalinity and hardness were the most prevalent compared to WHO and NESREA guidelines. The results showed that Tilapia had the highest concentration of heavy metals, followed by Silver Catfish and then Chinos. The descending order of metal concentration in fish samples was observed as follows: K Ca Na Mg Fe Zn Al Mn Ba U Tl Cu Se Pb As Ag Ni V Be. The HQ and HI values for children exceeded safe limits across all fish species, and CRI values for Arsenic and Lead also exceeded acceptable cancer risk thresholds. This study concludes that fish from Olooge Lagoon pose significant health risks, especially to children, due to bioaccumulated toxic metals. Regular environmental monitoring, pollution control, and provision of alternative clean water and fish sources are strongly recommended.