Objective To accurately identify mixed sources of heavy metal pollution in urban soils and verify the reliability of source apportionment models, this study focused on the soil in Harbin City. By integrating multi−dimensional data and Pb isotopic fingerprinting, we systematically revealed the distribution characteristics and source contributions of heavy metals, aiming to provide a scientific basis for urban soil pollution control.
Methods Sixty soil samples were collected in the study area, and the total amount of soil Pb isotopes, heavy metals Cr, Mn, Co, Ni, Cu, Zn, Cd, As and Pb elements and the total surface soil morphology were determined. Through the spatial distribution characteristics of heavy metals, multivariate statistical analysis and isotope tracing, the degree of heavy metal pollution and the source of heavy metal pollution in this region were analyzed.
Results The average contents of heavy metals Cr, Mn, Co, Ni, Cu, Zn, Cd, As and Pb in the study area were 55.2 mg/kg, 651 mg/kg, 9.63 mg/kg, 23.7 mg/kg, 31.0 mg/kg, 119 mg/kg, 16.1 mg/kg, 0.35 mg/kg and 45.6 mg/kg, respectively. In terms of spatial distribution, Cu, Zn, Cd and Pb elements had the highest content in the living area, and had similar high−value distribution points, while Cr, Mn, Co and Ni elements were relatively uniformly distributed spatially.
Conclusions The PMF receptor model showed that 35% of Mn, 35% Of As and 33% of Pb in the study area came from coal combustion. 45% of Zn and 32% of Cd come from traffic emissions; 73% of Cu, 43% of Zn, and 35% of Pb come from industrial production; 55% of Ni, 48% of Co, 47% of Cr, and 41% of As come from the soil−forming parent material. The results of the Pb isotope ratio in soil indicate that the anthropogenic sources of Pb in soil may be mainly from industrial emissions (including coal burning emissions and ore smelting).
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