Organophosphorus Pesticides Accumulation in Fish Species, South Part of the Caspian Sea and effect on the Acetylcholinesterase Enzyme (AChE)

In this study the distribution and accumulation of diazinon, malathion and azinfos methyl in mullet fish Liza aurata, caspian white fish Rutilus frissi kutum and common carp fish Cyprinus carpio from five estuaries along the Caspian Sea was investigated. Also, the effect of pesticides concentration on the acetylcholinesterase enzyme (AChE) in fish species was studies. Pesticides concentration varied with fish species, sampling station and toxin type. The results indicate that the pesticides concentration varied from 0.01 to 0.16 mg/kg for diazinon, 0.01 to 0.15 mg/kg for malathion and 0.05 to 0.36 mg/kg for azinfos methyl in three fish species. There was significant difference between different toxin concentrations in fish species, (P<0.05), and the order of toxic concentrations was as follows: azinfos methyl>diazinon>malathion. There was significant difference in toxin 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 indicate that the AChE enzyme concentration in all estuaries varied from 60.05 to 93.60 ng/ml for L. aurata, 91.47 to 95.41 ng/ml for R. frissi kutum and 70.09 to 83.8 ng/ml for C. carpio. There was negative correlation between pesticides concentration and acetylcholinesterase (AChE) enzyme level in fish species and correlation was (r=−0.885) for L. aurata, −0.920 for R. frissi kutum and (r=−0.874) C. carpio. The results confirmed that toxins bioaccumulation in fish species is strongly controlled by habitat and feeding habits. Also, the rsults showed that AChE enzyme activities in the fish tissues were gradually inhibited with increase in the organophosphorus pesticides concentration.