Lead isotope characteristics and source analysis of dust fall in different functional areas of a typical city in northern China.

The deposition of dust represents a significant fraction of the total atmospheric particulate load, and trace element pollution within it leads to significant environmental issues. In this study, the concentrations of ten trace elements, including V, Mn, Co, Cr, Ni, Cu, Zn, As, Cd, and Pb, were determined in dust fall samples collected from different functional areas of Baoding City. The characteristics and sources of trace element pollution in dust fall from different functional areas were further investigated. By analyzing samples collected from 16 strategically chosen sites in residential areas (RA), busy roads (BR), park areas (PA), and industrial areas (IA), we identified significant variations in trace element concentrations, with copper (Cu), lead (Pb), zinc (Zn), and cadmium (Cd) presenting considerable pollution levels. Comparison of trace element enrichment factors and the geo-accumulation index revealed spatial variations in trace element contamination across different functional areas. The pollution levels followed the order RA > BR > IA > PA. Although the total non-carcinogenic risk remained below the threshold, the total carcinogenic risk exceeded the acceptable threshold in several functional areas, especially busy roads and residential areas. Additionally, lead isotope analysis revealed that the dominant combined source group for Pb was coal combustion and traffic emissions, which together accounted for over 50% of the total contribution in most functional areas. Focused pollution mitigation policies are urgently required, particularly along busy roads and in residential areas, to minimize the adverse health impacts linked to trace element exposure. This research provides vital insights into regional environmental management approaches, essential for improving public health and urban sustainability in rapidly developing areas.