Pollution Characteristics, Health Risk Assessment and Source Apportionment of Heavy Metals in Urban Park Soil Particles of Taiyuan, China

To investigate the pollution characteristics, potential risks and source apportionment of heavy metals in soil particles from urban parks in Taiyuan, Shanxi Province, China, thirty soil samples were collected and processed into soil particles, and the concentrations of Cr, Ni, Cu, Zn, Pb, Cd, As, and Hg were subsequently measured. The results demonstrated that the mean concentrations of all eight heavy metals exceeded the natural lithogenic background values of Shanxi Province, with Hg, Cr, Pb and Cd exhibiting high variability. Obvious heavy metal accumulation was observed in the central urban area of Taiyuan, and Cd in park soil particles posed moderate to heavy contamination. The coefficient of variation (CV) values for Hg, Cr, Pb, and Cd were above 35%, and their enrichment factor (EF) values were greater than 1.5, implying that contamination of these four heavy metals was predominantly influenced by anthropogenic activities. The potential ecological risk index (RI) and contamination severity index (CSI) revealed that most sampling sites exhibited strong ecological hazards. Both non-carcinogenic and carcinogenic risks associated with heavy metals were within acceptable thresholds for both adults and children. Compared to adults, children were identified as being more vulnerable to heavy metal exposure than adults. Positive matrix factorization (PMF) analysis identified four primary sources: traffic emissions (Cu, Zn, Pb, and Cd), horticultural activities (Hg), natural sources (As), and industrial emissions (Cr, Ni), which contributed 33.53%, 27.03%, 15.62%, and 23.82% to the total heavy metal load, respectively. The findings of this study provide a scientific basis for the prevention, control, and management of heavy metal pollution in urban park soils.