Comparative assessment of potentially toxic elements geochemistry in various dusts in Southwestern Iran

Abstract Simultaneous measurements of the geochemical characteristics of different dust types remain limited. Direct sampling of atmospheric dust to assess potentially toxic element (PTE) concentrations is more costly and time-consuming compared to sampling other types of dust. The aim of this study was to investigate the relationships among acid-extractable PTE concentrations in deposited atmospheric dust (DAD), street dust (SD), and date palm-associated dust (DPAD), and to evaluate the potential of SD and DPAD to provide complementary information on PTE concentrations in DAD. Thirty-two DAD and 32 SD samples were collected seasonally from 12 cities in Khuzestan Province, southwestern Iran, over a one-year period, yielding a total of 128 samples for each dust type. Additionally, 32 DPAD samples were collected only once from the corresponding sites. Acid-extractable (pseudo-total) concentrations of Mn, Cd, Cu, Zn, Pb, Cr, Ni, and Co were measured using ICP-OES, particle size distributions were determined by laser diffraction, and data were analyzed using correlation, regression, principal component, and hierarchical cluster analyses. Mean PTE concentrations generally followed the order DAD > DPAD > SD, with DAD and DPAD exhibiting more similar values. DAD and DPAD contained higher proportions of fine silt, whereas SD contained a greater proportion of coarse silt. Correlation and regression analyses revealed element-dependent relationships among the three dust matrices. Mn showed weak and inconsistent correspondence, with low coefficient of determination (R² ≈ 0.01–0.10). In contrast, Zn, Cr, and Co showed strong correspondence between DPAD and DAD, with R 2 values of 0.67–0.88. Relationships for Ni, Pb, Cu, and Cd varied according to the elements and dust-matrix pairs examined. SD also showed relatively strong correspondence with DPAD for selected elements, particularly Zn and Cu, although the strength of these relationships differed among elements. Overall, the results indicate that DPAD and SD may provide complementary information for assessing the geochemical characteristics of DAD, but the extent of this correspondence is element-dependent. Because DPAD was sampled only once, whereas DAD and SD were sampled seasonally, the observed relationships do not establish seasonal correspondence or direct transfer pathways among the matrices. Further multi-season and multi-site investigations, together with independent validation, are needed before the broader applicability of these relationships or the quantitative prediction of PTE concentrations in DAD can be established.