Abstract:
This study investigated the elements of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in greenbelt soil in five types of functional zones in the urban area of Tianjin City, namely residential and educational zones, traffic greenbelts, industrial zones, parks, and river banks. The results are as follows. The overall accumulationof heavy metals in the greenbelt soil is in the order Hg>Cd>Pb>Zn>Cu, with the average content of As, Cr, and niapproximating to the background values. Pb, Zn, Cu, and as have the highest content in the greenbelt soil in industrial zones, while Cd, Hg, Ni, and Cr have the highest content in river banks. Heavy metals mainly migrate intogreenbelt soil by means of atmospheric deposition.Moreover, the accumulation coefficient of heavy metals in greenbelt soil is significantly correlated with the ratio of the average content of heavy metals in atmospheric deposition and the background value of the heavy metals in the soil. Meanwhile, the difference in heavy metal content between the greenbelt soil in different functional zones are mainly caused bythe difference in the quantity of the heavy metals in the atmospheric deposition. Besides, the greenbelt soil on river banks is also affected by sewage irrigation and river sediments, and industrial and household waste may also cause local accumulation of heavy metals.