Characteristics and health risks of heavy metal pollution in the soil of parks in Kaifeng City.

To investigate the impact of urban park soils on ecological quality and human health, representative parks with high visitor traffic were selected for this study. A total of 89 soil samples were collected, and the concentrations of seven heavy metals (Cr, Ni, Cu, Zn, Cd, Pb, and Mn) were determined using ICP-MS. Their contamination levels, ecological risks, and human health risks were assessed, and pollution sources were qualitatively identified. The results showed that the average concentrations of ω(Cr), ω(Ni), ω(Cu), ω(Zn), ω(Cd), ω(Pb), and ω(Mn) were 60.33, 30.38, 24.77, 88.51, 0.22, 56.81, and 692.74 mg/kg, respectively, all of which exceeded the local background values. The average order of Igeo for the heavy metals was as follows: Pb (0.86) > Cd (0.65) > Ni (- 0.32) > Mn (- 0.39) > Cr (- 0.45) > Cu (- 0.52) > Zn (- 0.60). The average pollution load index (PLI) was 1.83, with parks P4, P10, and P2 classified as moderately contaminated. Ecological risk assessment indicated that Cd posed the highest single-element risk, and parks P10 and P4 exhibited relatively high ecological risks, while the overall study area maintained a moderate risk level. Health risk assessment revealed that the hazard index (HI) values for both adults and children were below 1, suggesting no significant non-carcinogenic risk. However, the total carcinogenic risk (TCR) for children was more than ten times higher than that for adults. Chromium (Cr) was identified as the major contributing factor, and oral ingestion was determined as the primary exposure route. Monte Carlo simulation further highlighted that children faced higher cumulative non-carcinogenic risks than adults, with key influencing factors being ingestion rate (Ing) for children and dermal contact (SL) for adults. Both groups were within acceptable carcinogenic risk levels, with exposure duration (ED) being the most sensitive parameter.