大同市城区公园表层土壤重金属污染特征和健康风险及来源解析

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

  • 摘要:
      目的  为了解大同市城区公园表层土壤中重金属污染特征、健康风险和污染来源。
      方法  于2021年4月在大同市7个公园共采集54个0 ~ 10 cm表层土壤样品,测定铬(Cr)、锰(Mn)、钴(Co)、镍(Ni)、铜(Cu)、锌(Zn)、砷(As)、镉(Cd)、铅(Pb)含量,利用地累积污染指数法、潜在生态风险指数法和健康风险评价模型评价土壤重金属污染程度,并采用绝对主成分-多元线性回归模型解析重金属污染来源及其贡献率。
      结果  大同市公园表层土壤中9种重金属含量均高于山西省A层土壤背景值。其中,所调查的公园土壤中As、Cd和Pb含量分别是土壤背景值的2.27、18.93和2.77倍。文瀛湖公园表层土壤重金属污染最严重,其次是御河公园,Cd是主要污染因子。Mn对成人和儿童造成的非致癌健康风险最大,其次是As和Cr;经呼吸吸入途径造成的非致癌健康风险高于经口摄入途径和皮肤接触途径。
      结论  大同市各公园表层土壤中重金属对成人造成的非致癌健康风险指数均在可接受范围内,而对儿童造成的非致癌健康风险指数均远大于1.0,存在非致癌风险。Co对成人和儿童造成的致癌健康风险指数均大于1 × 10−4,存在致癌风险。大同市城区公园表层土壤中重金属的主要来源为土壤母质、交通和燃煤,其贡献率分别为48.93%、30.79%和20.28%。本研究结果可为大同市城区公园表层土壤污染控制和城市规划提供重要理论依据。

     

    Abstract:
      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.

     

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