The characteristics of heavy metal pollution in the intertidal zone of Dagu estuary

60 surface sediment samples and 2 cylindrical samples were collected from intertidal zone of Dagu estuary, Jiaozhou bay in May 2015, the particle size and concentrations of main heavy metals were measured.The distribution of sand and silty sand were better, and the separation of clay was poor.The concentrations of heavy metals were generally low in this survey, in which the average concentrations of Zn, Pb, Cu, Cr, Cd, As and Hg were 30.29×10^-6, 29.35×10^-6, 80.55×10^-6, 69.92×10^-6, 0.08×10^-6, 0.05×10^-6 and 8.63×10^-6, respectively.There was a strong negative correlation between the metallic elements in the surface sediments and the average particle size.The potential ecological risks of heavy metals were evaluated by Hakanson's method.The results displayed that almost all the metals were at low pollution levels except Hg.The environment has improved in recent years.