Health risk assessment and levels of toxic metals in whitefish (Rutilus kutum) in the Caspian Sea

In this article, the total concentration of toxic heavy metals such as lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As), which are mandatory elements of the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO), were determined to measure the health of the edible tissue of the Caspian Sea Rutilus kutum. 90 samples of Rutilus kutum were collected in three northern provinces (Gilan, Mazandaran, and Golestan) during 2021-2022. The concentration of Pb, Cd, Hg, and As of Caspian Sea Rutilus kutum samples were prepared by standard method and acid digestion. All samples were analyzed using flame, graphite furnace, and cold steam of the atomic absorption spectroscopy instrument. The results showed that 90% of all data samples (90th percentile) concentration of toxic metals in Rutilus kutum tissue decreased in the order of Cd >As>Hg>Pb. The amounts of Cd, As, Pb, and Hg in Rutilus kutum tissue were observed at not detected-0.31, 0.001-0.15, 0.001-0.060, and 0.001-0.020 mg/kg wet body weight, respectively. Also, the statistical analysis showed that two types of correlations were found between the concentration of metals and the total length and weight of Rutilus kutum: for Cd with total length (r=-0.46) and with fish weight (r=-0.51), for As with total length (r=0.30) and with fish weight (r=0.27), It showed negative and positive, respectively, but mercury and lead metals did not show correlation with biometric parameters. Comparing the current results with international standards showed that the four toxic metals Cd and As, Pb, and Hg were lower than the FAO and WHO standards concentration. The findings showed that the health risk assessment parameters (EDI, HQ, and THQ) for all metals were much lower than the recommended values. This showed that the consumption of Caspian Rutilus kutum in the study area did not have any adverse effects on human health due to the contamination of toxic metals.