Pollution Characteristics, Health Risks and Source Analysis of Surface Soil Heavy Metals in Urban Parks of Datong City

  Objective  The paper aims to understand the pollution characteristics, health risks and pollution sources of heavy metals in the surface soil of urban parks in Datong city.

  Method  Fifty four 54 surface soil samples of 0 - 10 cm were collected from 7 parks in Datong city in April 2021, and the concentrations of chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb) were determined. The Geo-accumulation index, Potential ecological risk index and Health risk assessment model were used to assess the heavy metal pollution, and the sources and contribution rates of heavy metal pollution were analyzed by the Absolute Principal Component Score-Multiple Linear Regression model.

  Result  The results showed that the concentrations of 9 heavy metals in the surface soil from parks in Datong city were all higher than that in the background values of A layer soil in Shanxi Province. The concentrations of As, Cd and Pb in the soils of the parks were 2.27, 18.93 and 2.77 times of the background value, respectively. Heavy metal pollution in surface soil of Wenying Lake Park was the most serious, followed by Yuhe Park, and Cd was the main pollution factor. Mn posed the greatest non-carcinogenic health risk to adults and children, followed by As and Cr. Inhalation posed the higher non-carcinogenic health risks than oral ingestion and dermal absorption.

  Conclusion  The non-carcinogenic health risk index of heavy metals in the surface soil of each park in Datong city for adults were all within the acceptable range, while the non-carcinogenic health risk index for children were all much higher than 1.0, indicating the non-carcinogenic health risk. The carcinogenic health risk index of Co for both adults and children was greater than 1 × 10⁻⁴, indicating the carcinogenic risk. The main sources of heavy metals in the surface soil of urban parks in Datong city were soil parent material, transportation and coal burning, and their contribution rates were 48.93%, 30.79% and 20.28%, respectively. The results of this study can provide an important theoretical basis for soil pollution control and urban planning in the urban parks of Datong city.