| This text chooses three function areas: an industrial area, a traffic-affected area and an agricultural area to study the contents of magnetic fractions in the soils and the relationship between magnetic enhancement and heavy metal accumulation. The results show that the soils from the three function areas are heavily polluted, with the pollution sequence of the industrial area＞the traffic-affected area＞the agricultural area. The soils in the industrial area are most heavily polluted, with Cr and Zn as main pollutants. The soils in the agricultural zone is mainly polluted by Zn and Cu. The soils in the traffic-affected area is mainly polluted by Cr and Pb. Magnetic susceptibility of the soils is positively significantly correlated with the amount of magnetic fractions in them at p＜0.01 level, suggesting that the magnetic enhancement is mainly attributed to the addition of magnetic particles. It was also observed that heavy metals are accumulated in the magnetic fractions in the soils. Further study indicates that there is a close relationship between heavy metal pollution and magnetic enhancement in the soils. The mean values of magnetic susceptibility of the soils from the three function areas are in the sequence of the industrial area＞the traffic-affected area＞the agricultural area. Moreover, some heavy metals in the industrial and traffic-affected areas are positively significantly correlated with magnetic susceptibility values. This suggests that it is feasible to monitor soil pollution in Shanghai with magnetic techniques. |
