The Features and Potential Ecological Risk Assessment of Soil Heavy Metals in Tianjin Suburban Farmland

The contents of soil heavy metals,such as As,Hg,Zn,Pb,Cu,Cr and Cd,in surface soil(0~20cm) from the main agricultural production farmland-Tianjin suburb Xiqing District,were investigated.Statistical analyses indicated that the mean contents of all metals are lower than their environmental quality secondary standard values for soils(GB 15618—1995),whereas exceeded that of their regional background values soil and the national soil.The contents of Cd,Cu,Hg in some soil samples have exceeded their soil secondary standardValues.Nemerow pollution index indicated that the level of most soil samples is at a clean level.The potential ecological risk index(RI) ranged from 12.96 to 104.5,indicating a low ecological risk level.