Health risk assessment and trace element analysis in tobacco products and user blood samples from urban and rural Karachi.

Cigarette smoking and use of smokeless tobacco products (STPs) such as gutka, mainpuri, and naswar are major public health concerns in Pakistan. This study assessed toxic trace elements (TTEs) Cadmium (Cd), Manganese (Mn), Lead (Pb), and Zinc (Zn) in the blood of male and female tobacco users and non-users from urban and rural Karachi, along with associated health risks. A total of 190 blood and 120 tobacco samples (30 cigarettes, 90 STPs) were analyzed. Cd, Mn, and Pb were measured using electrothermal atomic absorption spectrometry (ETAAS), and Zn by flame atomic absorption spectrometry (FAAS) after acid digestion. The study revealed significantly higher metal concentrations in urban users due to combined exposure from tobacco and environmental pollution. Cd levels in gutka (1.11 mg/kg) and cigarettes (1.035 mg/kg) exceeded WHO's limit (0.5 mg/kg). Urban male smokers had the highest blood Pb (0.108 ± 0.01 mg/L), over tenfold above the WHO limit, while urban females showed the highest Mn (0.031 mg/L). Rural male mainpuri users had the highest Zn level (2.76 ± 0.16 mg/L). Cd in cigarette posed the highest cancer risk (CR: 9.14 × 10⁻⁴); gutka users had a CR of 6.74 × 10⁻⁴. Female gutka users had the highest Pb intake (0.513 mg/kg/day). The findings call for urgent biomonitoring, regulation, and public health interventions.