Heavy Metals Concentration in Water, Sediment, and Fish around Escravos River, Nigeria

Edward Membere, Muhib Abdulwasiu

This study investigates heavy metals concentration in water, sediment, and fish around Escravos River, Delta State, Nigeria. Health risks to human via consumption of Clarias gariapinus were assessed through mean daily dose and allowable weekly intake. Twenty-seven (27) surface water, sediment and fish samples were collected from three locations over a 3 months period. The results of heavy metals concentration in water, sediments and fish ranges from 0.058 ± 0.001 - 0.121 ± 0.002 mg/L for Zn, 0.054 ± 0.04 to 0.092 ± 0.003 mg/L for Cu, 0.014 ± 0.02 to 0.032 ± 0.001 for Cd, 0.008 ± 0.001 to 0.077 ± 0.001 mg/L for Pb, 0.043 ± 0.001 to 0.065 ± 0.001 mg/L for Ni, 0.110 ± 0.00 to 0.161 ± 0.003 mg/L for Fe respectively. High Fe concentration was noticed in sediment 383.5 ± 0.71 to 509.0 ± 1.41 mg/kg and in fish 320.8 ± 1.06 to 403.2 ± 2.82 mg/kg, respectively. The results show that Hazard quotient (HQ) values for Cu, Cd, Pb, Fe, Mn and Cr were greater than 1 (HQ>1). Furthermore, cancer risk values observed for Pb, in fish samples were below allowable limit of 1.0 × 10−4 indicating no chance of carcinogenic effects. However, cancer risk for Cd, Ni and Cr were above allowable limit of 1.0 × 10−4 indicating chance of carcinogenic effects. These findings show that there are appreciable health risks associated or connected with consuming Clarias gariapinus, ingestion of surface water and sediment.