TOXICITY STUDY OF DIETHYL PHTHALATE ON CLARIAS GARIEPINUS FINGERLINGS (GENERAL EDUCATION PROJECT TOPICS AND MATERIALS)
ABSTRACT
Diethyl phthalate (DEP) is used as a plasticizer, a detergent base, in aerosol sprays, as a perfume binder and after shave lotion. It is known to be a contaminant of fresh water and marine ecosystem. Therefore, a study was designed to determine the acute toxicity effects of DEP on a fresh water fish, Clarias gariepinus fingerlings. The fish was treated with 50 μg/l, 75 μg/l, 100 μg/l, and 150 μg/l. DEP was dissolved in distilled water to determine the LC50. There was 100 % mortality observed in 150 μg/l, 56.6 % mortality in 100 μg/l treated fish, 46.7 % mortality at 75 μg/l, and 29.9 % mortality in 50 μg/l within 24h to 96h of exposure. The LC50 of DEP was estimated at log toxicant concentration as 2.217, 2.734, 3.435 and 3.931 μg/l at 24, 48, 72, 96h and 1.871μg/l for the total death. This shows that the impacts are dose and time dependent with respect to marked reduction in mortality rate. At sub-lethal concentrations of the test substance at 30 μg/l, 40 μg/l, 60 μg/l, and 80 μg/l in a renewal bioassay system, the water and the test compound were changed intermittently. One group was maintained as a control in dechlorinated water. Fish were killed and dissected to obtain liver, muscle, and brain samples. Brain and muscle acetylcholinesterase (AchE) activity was measured. Liver and muscle acid phosphatase (ACP) were measured. Liver aspartate (AST) and alanine transaminase (ALT) were measured. There was significant difference (P ≤ 0.05) in brain and muscle AchE activity compared to the control. The liver ACP activity was statistically significant (P ≤ 0.05) at day 15 respectively compared to the control.
