Exploring the heavy metals (Pb, Cd Cr, and Mn) content, kinetic dynamics and health risks in the cigarette butts in Bosnia and Herzegovina

Cigarette butts (CBs) have been recognised as a significant environmental pollutant. The various toxic substances, including heavy metals (HMs), are associated with CBs, thus determination of their content, leaching behaviour, and associated health risks is of great importance. The study investigates the composition, leaching kinetics, and health implications of CBs from the most popular electric and conventional cigarette brands among young in Bosnia and Herzegovina. The research included the determination of HMs content, the monitoring of leaching kinetics, simulated under both mildly and highly acidic conditions and the evaluation of potential health risks received during inhalation and dermal contact with water containing leached metals, through non-carcinogenic and carcinogenic risk assessment. The obtained results are as follows: (i) the HMs content in the examined CBs decreased in the following order: Mn > Cd > Cr > Pb; (ii) Kinetics of leaching, which are rarely reported, followed zero-order and first-order reaction kinetics with their respective half-lives. Organic acids were more favourable for Mn, while mineral ones were more efficient regarding Cd leaking process; (iii) an increased health risk from the observed carcinogenic elements (Cd and Cr), as well as a high non-carcinogenic risk from Pb was observed, particularly under highly acidic conditions.