Risk assessment and contamination drivers for heavy metals in kindergarten resuspended dust

It is essential for effective health risk management to precisely evaluate the health risks (HRs) associated with heavy metals (HM) contamination in kindergarten-resuspended dust (KRD) smaller than 100 μm and to identify the driving factors of contamination. The contamination levels and drivers of HM in KRD were investigated in a typical mega-city, and the content- and source-oriented HRs associated with the bio-accessibility (BA) of HM were evaluated. The results show that KRD is heavily polluted by Cd, Cr, and Ni. Furthermore, the BA in gastric solution is higher than that in intestinal solution due to the greater solubility of HM in the acidic environment. Industrial sources are the primary contributors to carcinogenic risks, with Cr and Ni being the main contributors. Notably, HRs based on total HM concentrations are greatly overestimated, so considering the BA of HM can provide more precise risk assessment results. Additionally, the spatial variations of Cr and Ni are primarily influenced by road density and industrial output, while the spatial variation of Cd is mainly affected by elevation, population density, and road density. This work underscores the critical importance of precisely assessing health risks and identifying the drivers of HM contamination in KRD.