Organophosphorus Pesticides (Diazinon, Malathion and Azinfos Methyl) Accumulation in Three Fish Species, in South Coasts of the Caspian Sea, Iran

In this study the distribution and accumulation of diazinon, malathion and azinfos methyl in mullet liza aurata, caspian white fish rutilus kutum and common carp cyprinus carpio from five estuaries along the caspian sea have been investigated. also, the effects of pesticides concentrations on the acetylcholinesterase enzyme (ache) in fish species were studies. pesticides concentration varied with fish species, sampling station and toxins types. the results indicate that the pesticides concentrations varied from 0.01 to 0.16 mg kg^-1 for diazinon, 0.01 to 0.15 mg kg^-1 for malathion and 0.05 to 0.36 mg kg^-1 for azinfos methyl in three fish species. there was significant difference between different toxins concentrations in fish species, (p<0.05), and the order of toxics concentrations was as follows: azinfos methyl>diazinon>malathion. there was significant difference in toxins concentrations between three fish species, and the highest toxins concentrations were absorbed in detritivores fish (l. aurata), followed by herbivorous fish (c. carpio) and carnivore fish (r. kutum). the results confirmed that toxins bioaccumulation in fish species is strongly controlled by habitat and feeding habits.