Distribution Characteristics of Heavy Metals in Soil of Heilongjiang Ecological Province and Its Ecological Risk Assessment

The contents of Hg,Cd,Pb,Cr,Cu and Zn in the soil of main cities in Heilongjiang Province were determined and their distribution characteristics were studied.The pollution environmental quality and potential ecological risk of heavy metals in soil of Heilongjiang ecological province were evaluated by using Nemerow integrated index method and Hakanson potential ecological risk index method.With the second grade standard values(6.5pH value7.5) of Chinese Environmental Quality Standard for Soils(GB15618-1995) as the background value,Cd accumulation in soil surface among 6 kinds of heavy metals was greater and Pb and Cr accumulation in soil were minimum.The integrated pollution index of heavy metals in one third of sampling sites reached the medium pollution degree and the others were slight pollution.The potential ecological risk of 6 kinds of single heavy metals was low and the potential ecological risk index of Cd was maximum.The heavy metal pollution in soil and the potential ecological risk in Heilongjiang ecological province were slight on the whole.