The present study was undertaken to assess the environmental hazards presented to wildlife by new pesticides or new uses of established pesticides, biochemical changes, residual behavior and accumulation of diclofop-methyl (Iloxan 36 % EC) . A laboratory trials of diclofop-methyl were carried out on tilapia fish, Oreochromis niloticus as indicator species to . Acute toxicity of diclofop-methyl (Iloxan 36 % EC) was carried out and the median lethal concentration for 96 hours (96 h - LC50) value was 1.89 mg / l. In the present study, two groups of fish were exposed to two sub lethal concentrations selected on the basis of 1 / 10 (0.19 mg / l, low concentration) and 1 / 3 (0.63 mg / l, high concentration) of diclofop-methyl LC50 value for 28 days under the laboratory conditions compared to the control group. The treatments indicated that a gradual bioaccumulation of herbicide with time in whole fish was more pronounced than in muscle. Several criteria for estimating pesticide accumulation effect were studied on different biochemical parameters in plasma of fish after treatments. The results indicated that alanine aminotransferases (ALT), alkaline phosphatase (ALP) and acetylcholinesterase (AChE) activities as well as albumin and glucose levels increased significantly after treatment with both concentrations comparing to control group. However, significant increase in aspartate aminotransferases (AST) and total protein levels with was recorded low concentration (0.19 mg / l) only. On the other hand, high concentration (0.63mg / l) caused significant increase in urea levels. However, ceriatinine level was decreased in both exposed concentrations. Noticeable changes in antioxidants biomarkers were recorded , a reduction in SH-protein level accompanied with an elevation in lipid peroxidation biomarker (MDA) were recorded in plasma after treatment with two concentrations. The previous results were accompanied with noticeable alterations in plasma and muscle protein patterns in both treated groups.
Key words: Diclofop-methyl, Herbicide, Bioaccumulation, Metabolic biomarkers, Fish, Oreochromis niloticus.