Heavy Metal Content Characteristics of Soil in Sewage Irrigation Area of Pearl River Delta

With the rapid industrialization development in recent years,there are many sewage irrigation phenomenons in the Pearl River Delta.It is important to understand the distribution of heavy metals in soil in sewage irrigation area for soil pollution prevention and control planning in Pearl River Delta.The total content and available content of heavy metals(Cd,Cu,Zn,Pb,Mn,Ni,As,Cr and Se)in soil from sewage irrigation area in the Pearl River Delta were analyzed with 32 soil samples.The average content of total content of the nine heavy met-als in soil from sewage irrigation area exceeded soil background value of Guangdong Province.Among of the nine heavy metals,Cd had the highest pollution degree,Se had the lowest pollution degree,Cd had the highest valid coefficient,and Ni had the lowest valid coefficient.The total contents of Cd,Cu,Zn and Pb decreased with the sampling depth increasing.The total contents of Ni,As,Cr and Se fluctuated or kept stable with the sampling depth increasing.The total content of Mn decreased firstly,and then rose remarkably with the sampling depth in-creasing.There was a remarkable or most remarkable positive correlation between total content and available content of Cd,Cu and Zn,and there was a remarkable positive correlation among of the total content of Cd,Cu and Zn,which indicated that the distribution of Cd,Cu,Zn and Pb in soil mainly affected by sewage irrigation.