Human health risk assessment of toxic metals in Nass smokeless tobacco in Iran.

Smokeless tobacco (ST) products create a deadly combination of addiction to nicotine and exposure to toxic substances. Nass is the predominant smokeless tobacco (ST) product consumed in Iran. This study was conducted to evaluate the levels of arsenic (As), lead (Pb), nickel (Ni), and cadmium (Cd) in Nass brands available in the Iranian market. A total of 42 samples were analyzed for the levels of heavy metals using flame atomic absorption spectrometry. The study also evaluated the risk associated with carcinogenic and non-carcinogenic toxic metal contamination in smokeless tobacco in Iran. The level of heavy metals measured in various Nass samples was ranked as Pb > Ni > Cd > As .The mean levels (range) of Pb, Cd, As, and Ni in Nass samples were determined to be 38.71 µg/g (17.60-57.70), 2.90 µg/g (1.20-3.65), 0.71 µg/g (0.25-1.17), and 23.24 µg/g (4.95-44.65), respectively. The levels of Pb, Cd, As and Ni in handmade samples are higher than products manufactured at the plant. The levels of Pb, Cd and Ni in all samples were higher than the Swedish Match recommended limits. While the levels of As in 12% of samples were lower than the standard defined by the Swedish Match. The Estimated daily intake (EDI) values for As, Cd, Ni and Pb are below the reference dose (RfD) established by the Environmental Protection Agency. The findings indicate that the target hazard quotient (THQ) and the hazard index (HI) values in the study were below 1. In this study, for the first time demonstrated that Nass consumers in Iran are at risk of exposure to Pb, As, Cd, and Ni. Consequently, the health system should prioritize raising public awareness about the health risks associated to Nass.