Environmental pollution and human health risks associated with atmospheric dust in Zabol City, Iran

Zabol City in eastern Iran has been recognized as one of the windiest, dustiest, and most unhealthy urban environments globally. This work examines the chemical speciation, environmental contamination, and human health risk associated with atmospheric dust in Zabol and surrounding areas, via analysis of 77 dust samples collected at 12 urban and rural sites from October 2018 to September 2020. On average, the concentrations of trace elements followed a decreasing order of Mn > Ba > Sr > Zn > Cr > V > Ni > Cu > Pb > Co > As > Mo > Cd, while abundant elements Al and Fe accounted for 5% and 2.9% of airborne dust, respectively. Significant enrichment factors were found for As and Cd and moderate for Mo. The ecological risk index indicated moderate pollution, with the highest contributions from Cd (68%) and As (25%). The intensive use of As-based fertilizers and pesticides in the agricultural lands in the Sitan Basin is the most likely source for the high As levels, while Cd, Pb, and Mo in airborne dust can be partly attributed to traffic-related contamination. Non-carcinogenic risk assessment revealed that ingestion is the primary exposure source of potentially toxic elements (PTEs) for both children and adults, with deleterious health effects, followed by skin contact and inhalation. The Hazard index (HI) for selected PTEs decreased in the order of Cr > As > Pb > Ni > Cd > Cu > Zn for both children and adults, classified within safe limits (HI < 1). However, Cr and As posed cancer risks above the safety threshold (> 10(- 4)) through ingestion exposure. Current results indicate that Zabol is still experiencing significant environmental and ecological contamination, as well as important health risks due to dust contaminated PTEs, necessitating appropriate mitigation strategies.