Spatial and temporal variation and potential ecological risk evaluation of heavy metals in surficial sediments from the adjacent waters of the Oujiang Estuary

This paper analyzed the distribution characteristics of Cu、Pb、Zn and Cd in surficial sediments from the adjacent waters of the Oujiang Estuary, and potential ecological risk level of those metals was evaluated based on the survey data in 2006,2013. The results showed the average concentrations of Cu and Zn had a slight increase from that in 2013 compared with that in 2006, but the difference had no remarkable significance with student's t test; then the contents of Pb and Cd significantly reduced. In common with other estuarys at home and abroad, the overall content of these metals in the study area was at a middle level. According to the spatial distribution of heavy metal contents, there was biggish difference between the two surveys. The potential ecological risk of heavy metals to the ocean ecology system was assessed with adopting Hakanson ecological risk index, the total potential ecological risk index as a whole was moderate level at 2013, what was significantly lower than that in 2006.