Water Quality Contamination and Mortality of African Mud Catfish (Clarias gariepinus; Burchell, 1822) Fingerlings Exposed to Paint Effluents

Abstract

The toxicological effects of paint effluents on Clarias gariepinus fingerlings and its aquarium water was studied. Ten fingerlings were used in each aquarium and exposed to 4 different concentrations of the effluent along with the control group. The fingerlings were exposed to 0%, 85%, 90%, 95% and 100% concentration of the effluent in a triplicate experiment. A total of 150 C. gariepinus fingerlings with a mean weight of 1.92 ± 0.34 g were used throughout the study. The physico-chemical parameters of the culture water varied with an increase in paint effluent concentration. Temperature, pH and conductivity increased with increasing concentration of effluent in most cases, while DO decrease with increase in effluent concentration. The mortality data trend of fingerlings exposed to the toxicant was concentration dependent. The 96 hours LC50 value with 95% confidence limit of C. gariepinus exposed to the effluent was 39.81% ± 12.68, and was significant with a determination coefficient (r2) of 0.95 at P<0.05. The high LC50 value for the fingerlings exposed to the paint effluent showed that the effluent is less toxic, but still caused mortality to the fingerlings at increased concentration. Although the paint effluents are less toxic, it was still able to alter the physico-chemical parameters of the culture water as well as cause mortality to fingerlings. As a result, the study emphasizes that paint industries should treat their effluents properly, reduce the microbial and chemical load before discharging into the environment. Also, the Government should enforce laws and regulations prohibiting indiscriminate discharge of untreated effluents by industries into drainage channels and any water body, because failure to enforce these laws could lead to the mortality of biological organisms, pollute organisms in surrounding water by altering the physico-chemical parameters and cause harmful diseases to humans that consume the resources from this polluted aquatic environment.