Bioaccumulation and Depuration Dynamics of Nickel Chloride in Nile Tilapia (Oreochromis niloticus) Exposed to Sub-lethal Concentrations

Abstract

The current objective of this research is to examine the bioaccumulation and subsequent depuration levels of nickel chloride within vital organs such as the gills, liver, and kidney of Oreochromis niloticus under controlled laboratory conditions. The fish were subjected to exposure under two sub-lethal concentrations, i.e., 1/5th (9.39 ppm) and 1/10th (4.69 ppm), for 28 days of absorption and subsequently transferred to uncontaminated, good aerated water for 28days of elimination (depuration). Following 28 days of exposure to lower sub-lethal and higher sub-lethal nickel chloride concentrations, the sequence of bioaccumulation of nickel chloride in organs was observed as kidney > liver > gills. The depuration trend for higher and lower concentrations was gills> liver > kidney. The kidney exhibited the highest accumulation of Ni. Meanwhile, the Ni depuration in the gills was significantly (p<0.05) more when compared to other routes following exposure to both concentrations. This research assessed nickel chloride's bioaccumulation and depuration dynamics in Oreochromis niloticus, providing insights into its physiological responses to metal exposure. The study concludes that nickel accumulates predominantly in the kidney, with gills exhibiting the highest depuration rates, highlighting the importance of understanding metal uptake and elimination mechanisms in aquatic organisms for effective pollution management.