Geochemical characteristics and source analysis of elements from dry and wet atmospheric deposition in the middle-high mountain and hilly region of Central Yunnan

Dry and wet atmospheric deposition is an essential input pathway for surface soil elements. To explore the geochemical characteristics and sources of elements from atmospheric deposition in the middle-high mountain and hilly region of Central Yunnan, this study investigated 35 dry and wet atmospheric deposition samples from three counties in Central Yunnan. The results show that nutrient elements exhibited high annual depositional fluxes, while heavy metal elements manifested low annual depositional fluxes, with their ranking as follows: TOC>Ca>K>I>F>Zn>B>Pb>Cr>Cu>As>Mo>Cd>Se>Ge>Hg. As revealed by the enrichment factors, principal components, and spatial distribution characteristics, Ca, Mo, B, As, and F originated primarily from soil dust; Cu, Cd, Pb, Cr, and Ge were mostly from anthropogenic sources, such as mining activities and coal dust; TOC, K, Se, and I came from both coal dust and soil dust, and Se was also affected by mining activities; and Hg stemmed from coal dust. Coal and copper-dominated polymetallic mineral resources spread extensively across the study area and are subjected to certain mining activities, which are intimately connected with the contents of heavy metals in the atmosphere. Therefore, targeted atmospheric monitoring should be conducted to ensure atmospheric quality and no pollution to soil.