TOXICITY ASSESSMENT OF THREE PESTICIDES ON AFRICAN CATFISH (CLARIAS GARIEPINUS)

Abstract

The toxic effects of dragon (A), sniper, (B) and kartodim 315ec, (C) on test specimens (Clarias gariepinus) of average weight 56.4 ± 31.1 g and length 18.5 ± 3.50 cm were examined. These pesticides have pervaded the markets, and have become common items in farms, homes, and food storage houses, hence are indiscriminately employed, mostly by rural and urban farmers and sometimes members of the society. Thus, they are potential environmental contaminants, and pose threat to the wellbeing of man and animals especially aquatic organisms. To determine their impacts in the environment, their respective acute toxicity tests were carried out according to the static non-renewable bioassay procedure. The experimental design consisted of a set of five concentrations [100, 200, 300, 400, 500 mg/L, and a control set up (0 mg/L) of pesticides A, B, and C (dragon, sniper, and kartodim 315ec respectively] with two extra replicate concentration and control for each set; in separate 30 L capacity calibrated rectangular tanks, each filled up to the 15 L mark. Each tank was distinctively labeled and loaded with 10 tests organism, making a total of 540-fish. The 96 h LC50 of pesticide B, (that is sniper) was found to be 27.0 mg/l.  The 96 h LC50 of A and C are less toxic as their respective 96 h LC50 was found to be 53.8 and 41.4 mg/l. The parameters considered include cumulative average value of operculum movement and tail beat frequency, and cumulative number of discoloration, erratic swimming, and mortality for each set of concentrations of the test substance: dragon, sniper, and kartodim 315ec respectively. The result shows that the lethal effect of the pesticides A, B, and C on the fish depends on concentration and duration of exposure to the substances as observation shows that the cumulative average number of discoloration, erratic swimming, and mortality increases with increasing concentration and exposure time, while the cumulative average of operculum movement and tail beat frequency decreases with increasing concentration and exposure time.