A Survey on Soil Heavy Metals in Vegetable Bases in Main Cities of Henan Province

A survey and comparative analysis on the soil security of vegetable bases in Zhengzhou,Luoyang,Jiaozuo and Pingdingshan etc.of Henan province were carried out.It was found that the content of heavy metals in the topsoil is higher than the national standard.The contents of Cd exceeded the standard in Gongyi and Pingdingshan,and the contents of Hg exceeded the standard in Luoyang.The comparative analysis among the contents of heavy metals in topsoil and sub-soil indicated that the heavy metals Cd,Zn,Cu,Pb,and Hg were obviously enriched in the topsoil.