Toxicological Impact of Leachates from Lemna Refuse Dump Site on African Catfish (Clarias gariepinus, Burchell 1882) Fingerlings Under Laboratory Condition

Abstract

Aim: The study investigated the toxicological effects of Calabar municipal dumpsite leachate on the fingerlings of Clarias gariepinus.
 Experimental Design: The study was set-up in a 6 × 2 Complete Randomized Block Design.
 Methodology: During the studt 120 C. gariepinus fingerlings were used. Each group was made up of 10 fingerlings. The fingerlings were exposed to 0% (control group), 15%, 20%, 25%, 30% and 35% of leachate in duplicate. Histopathology was also carried-out on the gills and liver of the fingerlings of each exposure group.
 Results: The temperature, pH, conductivity, and BOD increased with increasing leachate concentration, while the DO decreased with concentration. 5.17 ± 0.66 cm and 1.09 ± 0.40 g mean length and weight respectively of fingerlings were determined. Mortality depended on concentration. The 96 hours LC50 value with 95% confidence limit of C. gariepinus fingerlings exposed to leachate was 22.5% ± 0.89, and was significant with a determination coefficient (r2) of 0.93 at P<0.05. Leachates altered the orientation of gills and liver of the fingerlings.
 Conclusion and Recommendations: The low LC50 value of fingerlings exposed to different concentrations of leachate indicates a high toxicity of the leachate and altered the gills and liver of fingerlings. To this end, we recommended dumpsites are sited at a distance far from water bodies and areas inhabited by human, to mitigate the leeching of leachate into nearby aquatic systems. Law against indiscriminate discharge of waste into drainage channels and any aquatic system should be enforced by Government, to prevent mortality of biological organisms, extinction of species, contamination of organisms in nearby aquatic systems, changes in the physical properties, and health risk to humans that depends on resources from these aquatic systems for food.