ABSRACTSThe toxicity of commercial detergent effluent (containing Linear Alkylbenzene Sulfonates), a household cleaning agent was investigated with emphasis on histopathological effects using Juvenile African mud fish (Clarias gariepinus) with the mean weight 1.7 ± 0.2kg and standard length of 8.3 ± 0.3 cm. After series of range finding test, the fishes were exposed to lethal concentrations 0.00 mg/L, 0.01 mg/L, 0.02 mg/L, 0.03 mg/L, 0.04 mg/L and 0.05 mg/L and as well as sub-lethal concentrations 0.000 mg/L, 0.002 mg/L, 0.003 mg/L, 0.004 mg/L, 0.005 mg/L and 0.006 mg/L of detergent effluent for 56 days in a renewal bioassay procedure. The median lethal concentration (LC 50 ) values for lethal and sublethal tests were 0.0166 mg/L and 0.0038 mg/L respectively. Respiratory disturbance, erratic swimming, loss of equilibrium, lethargies and sudden fish death were observed in the exposed fish and these varied greatly with differences in concentration of the toxicant and this shows that mortality increases with an increase in concentration. The differences observed in the mortalities of C. gariepinus at varying concentrations were significant (p < 0.05), an indication that mortality could be a factor of concentration and time of exposure. The liver of the control fish showed normal parenchyma appearance of hepatocyte with normal staining patterns of the cell. In the treated fishes, there was congestion of central vein, vacoulation of hepatocyte, oedema, cellular infiltration and cellular necrosis. Detergent effluent is highly toxic to Clarias gariepinus juveniles, which are more susceptible to this household cleaning agent's effluent; therefore, an indiscriminate discharge of this effluent to the surrounding should be discouraged

The sublethal toxicity of soap and detergent effluents from a soap and detergent industry were investigated on Clarias gariepinus using a renewable static bioassay. The bioconcentration of metals in the head capsule and skeleton were significantly different (P<0.05). The result revealed that the skeleton had the highest concentration of Iron at 38.0x10 . It can be deduced that the fish species has the tendency to bioaccumulate heavy metals from a polluted environment, which may lead to the impairment of natural population size; thus consumption of fish from such polluted environment should be discouraged since their consumption could be deleterious to human health.

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This work aimed at evaluating the behavioral, biochemical and hematological effects of pharmaceutical effluent in laboratory population of Clarias gariepinus using a static renewal bioassay system. Fish specimens were collected and exposed to five (0.04, 0.06, 0.08, 0.10 and 0.12 mgL -1) sublethal concentrations of the effluent including a control experiment. Different dose dependent behavioral responses such as erratic swimming, gasp for breath, restlessness, and constant upward movement were observed in exposed fish. There was a steady decrease in the value of red blood cell (RBC), hemoglobin (Hb) and packed cell volume (PCV) as concentrations increase compared to the control stock. White blood cell count was found to be significantly (p<0.05) higher as the concentration of the test medium increases. Irregular level of lymphocytes and granulocytes across all concentrations was observed and levels of lymphocytes and granulocytes were significantly (p<0.05) increased in all effluent-treated fish samples during the exposure period. Different levels of total protein, glucose, cholesterol, etc., were obtained in the control and effluent-treated fish samples (p<0.05). The levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase (serum enzymes) and lactate dehydrogenase were significantly (p<0.05) higher in the exposed C. gariepinus. The hematological and biochemical alterations in the effluent treated C. gariepinus, which were strongly indicative of cellular damages. This might be attributed to toxic effects of the phamarceutical effluent. Consequently, direct discharged of untreated or partially treated pharmaceutical effluent should be discouraged as this calls for public health concern.