Evaluation of short and long-term effects of diazinon on cholinesterase activity in different tissues of freshwater Bivalve Anodonta cygnea (Bivalvia: Unionacea)

Document Type : Research Paper


1 Graduated with a MSc, Department of Fisheries, Faculty of Natural Resources, Karaj, Iran

2 Assisstant Professor, Department of Fisheries, Faculty of Natural Resources, Karaj, Iran


Diazinon is one of the highly consumed organophosphorous pesticides. It inhibits cholinesterase enzyme in animal tissues. Due to permanent residence in agricultural drainage channels, the swan mussel (Anodonta cygnea) can be considered as one of the most suitable indicators of such pollutants. At the present study, acethyle cholinesterase activity of A. cygnea was measured when exposed to various concentrations of diazinon (0, 1, 7, 15, 19, 23 mgL‑1) in different bivalve tissues, followed by comparison of short-term (first to fourth days) and long-term effects (7 to 21 days). The enzymatic activity was measured using the Elman's method of ELISA assay. Our results indicated that there was a significant difference between cholinesterase activity levels in bivalve's tissues at different concentrations of diazinon and exposure time. The specific activity of this enzyme in adductor muscle, digestive gland, foot muscle and gill were recorded as 27.285, 16.923, 2.792 and 1.914 nmol acethylethiocholine iodide hydrolyzed min-1mg‑1 protein, respectively. The adductor and foot muscle can be used as diazinon indicators after the exposure of A. cygnea to diazinon in environmental monitoring program. However, the gill among the other tissues, was the only one that was the appropriate tissue in determining the effects of low concentrations of diazinon (1 mg L‑1).