Toxicological Assessment of Clarias gariepinus Exposed to Leachates from Awotan Landfill, Ibadan, Oyo State, Nigeria.

Abstract

Background: This study aims to determine the physical and chemical characteristics of leachate samples from the Awotan dumpsite in Ibadan, Oyo State, Nigeria, and provide a comprehensive assessment of the effects of these leachates on the haematology of Clarias gariepinus. Methods: Two Leachate samples were obtained from a leachate section at the Awotan dumpsite, and the physical and chemical parameters of the samples were estimated using standard methods. Physical and chemical parameters such as temperature, dissolved oxygen (DO), electrical conductivity (EC), total dissolved solids (TDS), and pH were measured in-situ using a calibrated multi 3630 digital meter and probe. Turbidity was measured using a calibrated Secchi Disc. Other chemical parameters such as Cl–, NO3–, SO42-, and PO42- were taken to the laboratory and measured using the titrimetric method. Samples of juveniles were obtained from the Department of Aquaculture and Fisheries Management at the University of Ibadan and transported to the genetics laboratory at Lead City University, where they were acclimatized in chlorine-free borehole water for 21 days. After the acclimation period, the toxicity assessment setup was initiated. Five treatment bowls, including control (0%), 5%, 10%, 25%, and 50% leachate concentrations were set up in triplicates and 15 samples of Clarias gariepinus were introduced into each of the treatment bowls, where they were bred and observed for 21 days before taking them to the laboratory for haematology analysis. Results: The physicochemical properties of the leachate samples showed that EC (4200 ± 13.0), TDS (2450 ±14.4), NO3– (87.00 ± 5.7), and PO42-(3.134 ± 0.11) all exceeded the SON and WHO recommended standards. Also, the concentration of heavy metals such as Cu (9.28 ± 3.2), Mn (45.64 ± 6.3), and Fe (604.48 ± 10.62) all exceeded the SON and WHO recommended limit. Conclusion: The haematological test showed that high concentrations of the leachate samples significantly reduced the number of Red blood cells (RBC), Haemoglobin (Hb), White Blood Cells (WBC) and Packed Cell Volume (PCV) in Clarias gariepinus..