Journal of Aquatic Sciences 27(1)35-39 (2012)
ACUTE TOXICITY OF DIETHYL PHTHALATE ON CLARIAS GARIEPINUS FINGERLINGS
B. O. MGBENKA, C.B. IKELE AND N.S. OLUAH
Fisheries and Hydrobiology Research Unit, Department of Zoology, University of Nigeria, Nsukka.
Diethyl phthalate (DEP) is used as plasticizer detergent have in aerosol sprays, a perfume hinder and it is known to be contaminant of freshwater and marine ecosystem. The acute toxicity of diethyl phthalate to Clarias gariepinus fingerlings was investigated using static bioassays with continuous aeration over a period of 96 h. The fish was treated with graded concentration of DEP (0, 50, 75, 100 150mg/l) to determine the LD50. The LD50 of DEP for Clarias gariepinus determined at 95% confidence limit 24 h, 48 h, 72 h and 96 h. The LD50 after 24 h, 48 h, 72 h and 96 h were 2.22, 2.73, 3.44 and 3.93µg/l respectively. The mean LD50 1.87 µg/l. There was no mortality in the control group but there was significant difference (P<0.05) in the mortality in the treatment group. The mortality which was dose dependent was 29.9% and 100% in 50 µg/l and 150 µg/l DEP respectively. During the exposure period, the test fish was restless and swam erratically. Also, there was haemorrhaging of the gill filament. These observationS are indicative of stress due to the effect of the diethyl phthalate on the fish.
Key Words : Toxicity, Clarias gariepinus, diethyl phthalate, stress, mortality