Studies On Heavy Metals Pollution In Surface Sediment From Typical Ecologically Regions Of Yantai Coastal Zone

The coastal is interaction zone between sea and land, which is a typical geographical unit connecting, composite and crossover between Marine ecological system and terrestrial ecosystems, with the sea-land transition region unique vulnerability and sensitivity, Yantai coastal zones is certain typical research area. In recent years, with the rapid development of industry and the acceleration of urbanization, a lot of municipal sewage and industrial waste water is discharged into offshore, causing a degree of pollution and damage of offshore marine areas. Investigation of heavy metals pollution situation in sediments, discusses the source of heavy metals, and make an assessment of heavy metals pollution condition assessment of the typical ecologically sensitive regions of Yantai coastal zone has certain value and significance for coastal Marine environmental protection and resource rationally develop.This study collected the surface sediment samples from the typical ecologically sensitive regions of Yantai coastal zone, the concentration of Cr, Co, Ni, Cu, Zn, Cd, Pb were determined by the microwave digestion and ICP-MS, and the distribution of heavy metal speciation were analyzed by the Tessier sequential extraction method, cold diffusion method for the determination of sediment AVS and SEM content. The sources of heavy metals pollution source, the distribution of heavy metal speciation and biological efficiency were analyzed, and the cumulative index method and potential ecological risk index method is used to evaluate the heavy metal pollution condition. Results show that the concentration of heavy metals in the surface sediment samples from the typical ecologically sensitive regions of Yantai coastal zone in order for Zn >Cr> Cu> Pb >Ni >Co>Cd, in estuary and wastewater discharging area, Cd and Cu has higher levels of concentration. The concentration of heavy metals in other regions were lower, and basically be same to other research areas. The elements significant correlation between heavy metals,showing the similar of source of heavy metals.The distribution of heavy metal speciation in the surface sediment samples from the typical ecologically sensitive regions of Yantai coastal zone show that , the extractable phase proportion of Cd is relative higher, and the bioavailability of Cd was highest in these heavy metals, other metals were mainly exist in residual fraction. AVS/SEM values are larger than 1, show that the biological efficiency of heavy metals in the coast zone is not high.Based on the evaluation of heavy metals pollution in the surface sediment samples from the typical ecologically sensitive regions of Yantai coastal zone showed that Cd in surface sediments of the estuary and wastewater discharging area have been polluted, other heavy metals have no pollution, the three regions with low potential ecological risk to the environment.