NICKEL LEVELS AND HISTOPATHOLOGICAL STUDIES IN FISH ORGANS

ABSTRACT

Over the years there has been an increase in the level of heavy metals in freshwater ecosystems in Nigeria. This study is aimed to assess the concentration of Nickel in aquatic organism (Schilbe uranoscopus) collected from Ikpoba and Ogba Rivers, Benin City Nigeria, for a period of three months (November 2021, December 2021 and January 2022). The concentration of Nickel in water samples were done using Atomic Absorption Spectrophotometry (AAS). Physico-chemical parameters such as pH, total dissolved solids, total suspended solids, balanced oxygen demand, chemical oxygen demand etc were also determined of both rivers. Fish (Schilbe uranoscopus) were gotten from both rivers to determine the impact of nickel on it's organs, histopathology was used to ascertain the level of damage done on the organs (gills, liver, reproductive organs) of the Schilbe uranoscopus . The concentration of Nickel in water in both rivers ranged from 0.023 - 0.670 mg/L, the Schilbe uranoscopus obtained from both also had significant levels of Nickel ranging from 1.876mg/kg to 8.162mg/kg. Histopathological investigations indicated that the gills, reproductive organs, and liver were affected by nickel, resulting in various forms of tissue damage. There was a significant relationship between the concentration of Nickel in the water bodies and in the fish organs. The edible fish species in both rivers are unfit for human consumption. Effective measures such as legislative provision and other waste management tools for environmental protection should be implemented for the wellbeing of dwelling flora and fauna and ultimately the health of local populations.