Magnetic Susceptibility and its Relationship with the Concentration of Selected Heavy Metals and Soil Properties in Surface Soils of the Isfahan Region

In order to investigate the soil magnetic susceptibility and its relationship with the concentration of selected heavy metals and soil properties, a total of 158 composite surface soil samples (0-5 cm) were taken from an area of about 700 km2. Locations of the sampling sites were determined using a GPS and their land uses were recorded. The in situ magnetic susceptibility for the topsoil samples was measured by Bartington MS2F sensor in the field. Magnetic susceptibility (?lf) was also measured at low frequency (0.46 kHz) using a Bartington MS2 dual frequency sensor. Besides, the concentration of total copper (Cu), zinc (Zn), lead (Pb), manganese (Mn), iron (Fe), nickel (Ni), chromium (Cr) and cobalt (Co) was measured in all the soil samples. Selected soil properties including pH, electrical conductivity, organic matter, calcium carbonate equivalent and gypsum were also determined to understand the relationships between magnetic susceptibility and soil properties. The concentration of Cu, Zn, Pb, Mn and Fe are positively correlated with magnetic properties which could be attributed to an input from traffic emissions and industrial activities. A significant negative correlation was found between ?lf and gypsum and electrical conductivity. This could be due to the fact that any increase in soluble salts and gypsum in soil causes the dilution effect for magnetic minerals. Moreover, the results of multiple regression analysis between ?lf with heavy metal concentrations and soil properties indicated that LnPb, LnZn, LnFe and Cr and percentage of sand, gypsum and SOM could explain approximately 76% of the total variability of ?lf in the study area. The results of the in situ magnetic susceptibility showed that 71% of the total variability of MS2F could be explained by LnPb, LnMn and percentage of sand, gravel, gypsum and SOM in the study area.