Magnetic Property of Urban Soil Profile in Bengbu City and Its Environmental Significance.

In order to study the impact of human activities on urban soil environment, the soil profile of a plot of dry-land dug at the foot of the Zhuizi Mountain (117.46°E, 32.91°N) in Bengbu City was investigated to examine its property regarding the content of mineral components and heavy metal elements (Zn, Pb, Cr, Ni, Cu); additionally, its magnetic parameters were measured including low-frequency volume magnetic susceptibility (K_L), high-frequency volume magnetic susceptibility (K_H), anhysteretic remanent magnetization (ARM), isothermal remanent magnetization (IRM, SIRM), temperature-dependent magnetic susceptibilities (k-T curve), and the measured data were calculated and statistically analyzed. The findings of the study reveals that the soil profile mainly consists of minerals such as quartz, albite, potassium feldspar, illite and montmorillonite; owing to the influence of human activities in the City, the content of Zn and Pb in the top soil was significantly increased; magnetic minerals in the soil includes magnetite hematite, goethite and lepidocrocite, but was relatively low, the magnetic properties of the soil profile are mainly dominated by ferrimagnetic minerals. According to the variation of magnetic parameters related with depth of the soil profile, the soil profile can be divided into two layers: 0-20 cm being the first layer, 20-80 cm the second layer. The magnetic property of the second layer of soil is mainly determined by the soil parent material, on the other hand, the first layer of soil has been affected by strong magnetic particles brought about by urban human activities, the average values of x, SIRM and XARM being remarkably higher than those of the second layer, while X_fd and X_ARM/SIRM average values lower than those of the second layer, reflecting an increase in the content of magnetic mineral and coarsening of particles in the first layer of soil. The facts of magnetic parameter values vary with depth of the soil profile within 0-20 cm reflected the process and degree of influence on the dry-land soil profile, exerted by urban human activities. [ABSTRACT FROM AUTHOR]