No abstract

Urban soils are an integral ingredient of the urban ecosystem, and whether heavy metals do harm to the city inhabitant health has been brought to the forefront. A total of 78 urban soil samples were collected from Zhengzhou, and the contamination level, source apportionment, concentration-oriented and sourceoriented risk evaluation of pollution elements in the samples were carried out in the study. Results showed that Cd was the most serious contaminant and constituted considerable ecological risk compared to other elements. Four Factors (natural source, industrial production, agricultural activities and traffic discharges) were distinguished through the positive matrix factorization model in conjunction with correlation analysis, and their respective contribution rates were 18.73%, 33.22%, 23.91% and 24.14%. The probability distribution of health risk assessed by means of Monte Carlo simulation revealed that noncarcinogenic risks associated with heavy metals were acceptable for both adults and children, while the total carcinogenic risk values remained relatively high. Moreover, the children were more susceptible to health risks in comparison to adults, and the ingestion way was considered to be the major exposure pathway. The results of source-oriented health risk demonstrated that the agricultural source was the major contributor to health risks, which was characterized by As, Ni and Co.

Urban soils are an integral ingredient of the urban ecosystem, and whether heavy metals do harm to the city inhabitant health has been brought to the forefront. A total of 78 urban soil samples were collected from Zhengzhou, and the contamination level, source apportionment, concentration-oriented and source-oriented risk evaluation of pollution elements in the samples were carried out in the study. Results showed that Cd was the most serious contaminant and constituted considerable ecological risk compared to other elements. Four Factors (natural source, industrial production, agricultural activities and traffic discharges) were distinguished through the positive matrix factorization model in conjunction with correlation analysis, and their respective contribution rates were 18.73%, 33.22%, 23.91% and 24.14%. The probability distribution of health risk assessed by means of Monte Carlo simulation revealed that non-carcinogenic risks associated with heavy metals were acceptable for both adults and children, while the total carcinogenic risk values remained relatively high. Moreover, the children were more susceptible to health risks in comparison to adults, and the ingestion way was considered to be the major exposure pathway. The results of source-oriented health risk demonstrated that the agricultural source was the major contributor to health risks, which was characterized by As, Ni and Co.