DISTRIBUTION PATTERN AND RISK ASSESSMENT FOR HEAVY METALS IN THE SURFACE SEDIMENTS OF JIAOZHOU BAY

In this paper, the distribution patterns of heavy metals of Hg, Cd, Pb, Zn, Cu, Cr and As taken from 150 surface sediment samples of Jiaozhou Bay are analyzed for assessment of environment qualities. The pollution level and ecological risk of the heavy metals are evaluated with the geological accumulation index and the potential ecological risk index. The results show that the amount of heavy metal elements in surface sediments of Jiaozhou Bay gradually decrease from coast towards the sea in general, and is relatively higher in the eastern nearshore area comparing to the western. According to our evaluation, the overall quality of sediments in Jiaozhou Bay is quite good, and the sediment quality according to average content of heavy metal elements belongs to the first type of sediments stipulated in Specifications of Marine Sediment Quality (GB 18668—2002), except for the sediments in the eastern part, which may reach the second or even the third type of sediment according to the standards. The overall heavy metals pollution levels of the sediments are clean to light polluted, and the integrated potential ecological risk is low. Since 1980s, human activities have become the main factor affecting the distribution of heavy metals in the surface sediments of Jiaozhou Bay.