ABSTRACT: Due to the fish are often at the top of the aquatic food chain and may accumulate large amounts of heavy metals from the water, this study was conducted to determine of Cd, Cr, Pb and Ni contents in the muscle of imported tilapia fish marketed in the city of Hamedan in 2017. In so doing, totally, 27 muscle samples from nine different brands of tilapia fish were randomly collected from the market basket of the study area. After preparation and processing the samples in the laboratory, the concentration of metals, was determined using inductively coupled plasma-optical emission spectrometer. The results showed that the mean concentrations (mg/kg) of Cd, Cr, Pb, and Ni in samples were 0.26 ± 0.09, 1.54 ± 0.15, 0.55 ± 0.11, and 0.67 ± 0.20 respectively. Also, the mean contents of Cd and Pb were higher than the maximum permissible levels (MPL) established by the World Health Organization (WHO). The computed health risk index values showed that no potential health risk for adults and children via consuming the muscle of tilapia fish at the current consumption rate for the study area. Based on the results, due to the mean contents of Cd and Pb in the muscle samples of tilapia fish were higher than the MPL, therefore, serious attention to the reduction of the discharge of hazardous substances in the aquatic ecosystems and also periodic monitoring of chemical residue particularly toxic heavy metals in the highdemand food is recommended.
