Form Distribution Characteristics and Influencing Factors of Cd, Cr, Pb, As and Hg in Farmland Soil from the Shijiazhuang Area, China (Vol. 42, No.6)----Institute of Geochemistry Chinese Academy of Sciences

CAI Kui1, DUAN Ya-Min2, LUAN Wen-Lou3, CHEN Long3,ZHANG Xu3, ZHAO Xiao3, ZHANG Yong Xi3

（1.Institute of Geological Survey，Shijiazhuang University of Economics ,Shijiazhuang 050031, China；
2.Postgraduate academy，Shijiazhuang University of Economics, Shijiazhuang 050031, China；
3.Institute of Natural Resources and Environmental Engineering，Shijiazhuang University of Economics ,Shijiazhuang 050031, China)

Abstract: Soil pollution by heavy metals has been an environmental problem all over the world. With deep-going research on the transport and transform of heavy metal elements, metal toxicity was recognized to be not only related to the total amount of metals, but also mostly depend on their chemical forms. In this paper, the authors took the farmland area in Shijiazhuang City, Hebei Province, as a study area to investigate the chemical forms of soil heavy metals (Cd, Cr, Pb, As, Hg) and their influencing factors in 31 root soil samples analyzed. The results showed that the available content of Cd accounts for the largest proportion in the total amount up to 40.94%, followed by 12.73% of Pb, while Cr, Pb, As, Hg were dominated by residual fraction; There was a significant correlation between the speciation and total amount of five kinds of heavy metals, especially Pb . There were significantly negative correlations among the carbonate- bound form, strongly bound-organic state and humic acid of soil pH and Cd, Cr, Pb elements, the order affected by pH is Cr > Pb > Cd. There was a significantly positive correlation between the residual fraction content of heavy metal elements and Fe2O3 content. Five kinds of heavy metal exchange species and TOC are of negative correlation. There was a positive correlation between CEC and the water soluble state and residual state of heavy metal elements. Clay content is negatively correlated to the exchange state of Cr, and positively correlated to the residual state of each element.

Key words: Shijiazhuang; heavy metal; speciation; influencing factor

EARTH AND ENVIRONMENT Vol. 42, No.6, Tot No.302, 2014, Page 742-749