The magnetic characteristics and heavy metal elements of surface soil samples in Baoji urban street greenbelts were systematically analyzed in order to explore the feasibility of using magnetic parameters to indicate heavy metal pollution in urban street greenbelts soil. The results of the study showed that ferromagnetic minerals with low-coercivity and coarse magnetic grains dominated magnetic properties of the samples. The average values of low-frequency magnetic susceptibility (χ lf ) was 200.65×10 -8 m 3 /kg, which was much higher than the background value. The spatial variation of magnetic mineral content was remarkable, with high levels observed in heavy traffic areas and industrial gathering areas, and low content in areas heavily covered by short vegetation, which was basically consistent delineated by pollution load index (PLI). Magnetic parameters χ lf , saturated isothermal remanent magnetization (SIRM) and soft remanent magnetization (SOFT) can be used as the effective indicators for monitoring heavy metals pollution in soil of urban street greenbelts.

The concentration of heavy metals in plants’ leaves can effectively indicate the spatiotemporal differences of environmental pollution, providing a scientific basis for the monitoring of urban air quality. The concentration of Ni, Cu, Cd, Pb and Zn in the leaves of five different species (Ophiopogon japonicus, Ligustrum vicaryi, Platanus acerifolia, Sophora japonicaand Cedrusdeodara) were measured, which were from I, II, III, IV (0.05 m, 0.25 m, 1 m, 4 m) at different times (May and November) in the green belt of Baoji city. The degree of heavy metal pollution and potential ec ological risk were analyzed. The results revealed that the concentration of Zn, Cu and Pb in roadside plant leaves was relatively high. In May, the heavy metal concentration was the highest in the leaves of C.deodara, whereas this was the case for S. japonica in November. Arbors were more effective at capturing particles from the atmosphere than low plants. At the same height, areas with high levels of heavy metal pollution in May were basically the same as that in November, and areas with high levels of pollution were affected by traffic and industry. The pollution index and the comprehensive index of potential ecological risk of element Cd were the highest, indicating that the potential harm of Cd to the environment should receive more attention from the Government.