Heavy metals investigation in Sarotherodon melanotheron obtained  from Ayetoro River, Ilaje, Ondo State

Akinjagunla  Akinmoladun; Igiogbe  Aganwonyi; Emmanuel  Nwankwo; Peter  Ayadi; Selina  Omonmhenle

Akinjagunla Akinmoladun National Centre for Energy and Environment, Energy Commission of Nigeria, University of Benin, Benin City, Edo State, Nigeria
Igiogbe Aganwonyi National Centre for Energy and Environment, Energy Commission of Nigeria, University of Benin, Benin City, Edo State, Nigeria
Emmanuel Nwankwo National Centre for Energy and Environment, Energy Commission of Nigeria, University of Benin, Benin City, Edo State, Nigeria
Peter Ayadi Department of Chemical Sciences, School of Sciences, Olusegun Agagu University of Science and Technology, Okitipupa, Ondo State, Nigeria
Selina Omonmhenle Department of Chemistry, Faculty of Physical Sciences, University of Benin, Benin City, Edo State, Nigeria

Keywords: Heavy metals, Sarotherodon melanotheron, Ayetoro, River, Bioaccumulation, Anthropogenic

Abstract

This study was conducted in Ayetoro River in Ilaje local government area in the southern part of Ondo State, Nigeria, for five months (May 2021 - September 2021) to investigate the concentration of heavy metals in Sarotherodon melanotheron. This species of fish is commonly consumed by a large section of the population of Ilaje people, being that they live close to Ayetoro river; whereby 95% of the populace are fishermen. The accumulation of heavy metals in fishes is an important problem because many fishes tend to accumulate the non-essential metals in their organs. The accumulation above the recommended limit for both essential and non-essential metals may pose health hazard to consumers. Sixty (60) Sarotherodon melanotheron were collected using gill-net during the wet season. The level of heavy metals copper (Cu), lead (Pb), cadmium (Cd) and iron (Fe) in the muscle tissue of the fish were determined using Atomic Absorption Spectrophotometry technique (AAS). Only cadmium was not detected out of the metals examined. Bioaccumulation of iron was found to be higher in the month of July (0.890 ± 0.241ppm) compared to other months. Copper showed a significant difference in concentration across the months of investigation, most especially in the month of June (0.181 ± 0.058ppm). Lead also revealed constant concentration (0.002 ± 0.001ppm) across the studied months. The results obtained from this study showed the values of the examined metals (Pb, Cu, Fe, Cd) in the S.melanotheron fish samples are high. Fe, Cu and Pb were found to be higher than the permissible limits (p< 0.05, 0.03, and 0.001ppm respectively) recommended by Food and Agricultural Organization (FAO) and World Health Organization (WHO). This can be attributed majorly to anthropogenic activities like release of industrial wastes and the exploration activities that is being carried out in the region. The accumulation of heavy metals in the tissues of organisms can result in chronic illness and cause potential damage to the population. Therefore, regular monitoring of heavy metals concentration in S. melanotheron is necessary and members of this community need to be conscious of the dangers of long-term exposure to these heavy metals through the consumption of this sample specie.