ACUTE TOXICITY OF PROPANIL TO THE JUVENILES OF NILE TILAPIA (Oreochromis niloticus

Abstract

The widespread increase of pesticides application in crops frequently leads to the contamination of the fresh water ecosystem. One of the most commonly used pesticides in Nigeria is propanil. Acute toxicity of propanil (3, 4-dichloropionanilide) to juveniles of Oreochromis niloticus was determined in a 96-hour static bioassay. During the assay opercular ventilation rate of the fish was determined. The 48-hour and 96-hour LC50 of propanil to the juveniles of O. niloticus were observed to be 11.22mgL-1 and 5.79mgL-1 respectively. The physico-chemical properties of the borehole water used were also observed for the duration of the experiment. The highest and lowest of all observed parameters were as follows: Temperature recorded 27.73 ± 0.300C in 12.50 mg/l and 26.05 ± 0.440C in the control, pH recorded 7.27 ± 0.02 and 6.54 ± 0.09 for 15.00 mg/l and control respectively, DO record was high in the control with 7.45 ± 0.19 and low in 15.00 mg/l with 5.58 ± 0.10, while conductivity was also 3.37 ± 0.02 for15.00 mg/l and 3.17 ± 0.01 for control, 7.5 mg/l had 33.46 ± 0.02 and control had 31.13 ± 0.08 for alkalinity, and finally hardness recorded 24.41 ± 0.04 and 20.30 ± 0.10 for 15.00 mg/l and the control experiment respectively. Other behavioural response of the exposed fish include loss of equilibrium, agitated swimming, air gulping; visible blood lines on the gills, pectoral and pelvic fins, swollen and ruptured swim bladder. These results show that the contamination of water by pesticides either directly or indirectly be lethal to fish and may reduce fish IJABR Vol. 6(2):71 – 79 (2014)