Indian Journal of Science and Technology

Abstract

Metal company effluent toxicity in Clarias gariepinus, was investigated by the hematological parameters after long-term (8 weeks) exposure to various effluent sub-lethal concentrations (3.5397, 7.0794 and 14.1589ml/L effluent). Test groups were set up in duplicates for each concentration, plus the control group. Blood samples were collected from four individuals bi-weekly for each concentration at 0, 2, 4, 6, and 8th weeks of exposure. Most of the investigated physico-chemical characteristics of the effluent showed deviation from the FEPA (1991) limits. The effluent caused a mean decrease of haematocrit (30.02 ± 1.21% to 24.75 ± 4.57%), haemoglobin (10.02 ± 0..95g/100ml to 8.60 ± 1.34g/100ml), mean corpuscular haemoglobin (74.00 ± 8.64pg/cell to 30.45 ±12.75Pg/cell). Erythrocytes increased from 135.08 ± 10.55 to 367.42 ± 94.88 and then decreased to 219.07 ± 48.66 x 103 cells/mm3 . Leucocytes also followed a similar pattern. The MCV and MCH also varied significantly (P > 0.05). The leucocytes peak (103.0 x 103 cells/mm3 ) was recorded in week 4, in fish from the highest concentration tank. The study suggested that the metalfinishing effluent has strong influence on the hematological parameters in C.gariepinus.
Keywords. Industrial effluent, FEPA, hematology, fish, Clarias gariepinus