A preliminary study of the distribution and pollution source of heavy metals in soils of Jiangsu Provin

Abstract：Based on data of 24186 topsoil (0～20 cm in depth) and 6127 deep soil (150～200 cm in depth) samples from whole Jiangsu which contain such elements as Cd, Hg, Pb, As, Cu, Zn, Cr, and Ni, the authors studied the distribution and pollution characteristics of heavy metals in soils by analyzing their spatial variation and pollution source. Some conclusions have been reached： First, the spatial distribution of heavy metal elements is relatively uneven within natural environmental soils and anthropogenic environmental soils of Jiangsu, and the nonuniformity in anthropogenic environmental soils is higher than that in natural environmental soils. Second, a part of farmland soils (1.02% or so) has been badly polluted by some heavy metal elements such as Cd, Hg and Pb, and the pollution from Suzhou and Wuxi is the most severe in all soils of Jiangsu Province. Third, human activities in the industrialization and expansion of cities and some natural geological processes with the formation of parent soil are both important factors responsible for local pollution of heavy metals, and there exist obvious differences between man-made pollution and natural pollution in soils. It is thus held that natural pollution of heavy metals is characterized by planar, polymetallic and double-layer soil pollution with relatively low concentration, whereas things are quite different for man-made pollution.