Addressing capacity assessment uncertainties in high-geological-background areas, this study develops a source-oriented risk assessment framework integrating spatial interpolation, source apportionment, and dynamic capacity modeling. Analysis of 39 surface soil samples (As, Cr, Ni, Cu, Zn, Cd, Pb, Se, pH) from ankang basin, China, reveals: Two heavy metal sources were quantitatively identified via APCS-MLR. Natural sources (71.94%) dominate, contributing Se, Cd, Cu, Zn, and Ni, with Cd primarily geogenic. Anthropogenic sources (28.06%) from industrial, transportation, and agricultural activities contribute Cr, As, Pb, and Ni. Static capacity assessment identifies Cd as the primary limiting element (average capacity 0.22). Dynamic model predictions indicate that the 20-year dynamic capacity of all elements is only 14–20% of the theoretical static capacity (Qi), representing 16–47% of the current existing capacity, and will approach dynamic equilibrium after 40 years. Source-oriented capacity indices reveal natural sources pose the highest comprehensive risk (SPI = 0.916), mainly driving Cd capacity stress (SPICd = 0.34). Anthropogenic sources remain safe (SPI > 1.255) but warrant Pb monitoring. This framework supports precise management of selenium-rich lands, shifting strategies from emission control to avoiding high-risk geological units.
Chen et al. (Mon,) studied this question.