| The region of eastern Guangdong province is one of thickly populated district in China, which develops fast in economy. After nearly three decades of economic reform and booming industrial development, a tremendous amount of waste was discharged to the coast, which resulted in serious environmental problems. This phenomenon is especially significant in heavy metal pollution, because heavy metals were not decomposed, but were accumulated and their toxicities can be magnified through food chain. Therefore, it is necessary to investigate the content, speciation, and time-space distribution of heavy metals in sediment that the place of heavy metals accumulating. The result would make a great contribution to understand the heavy metal resources, pollution status and the affection to the ecosystem, and have a great significance to marine environmental protection and ensure to sustainable development of marine economy.The whole studied area along the coast of eastern Guangdong province was divided into four representative regions: Shantou harbor, Hanjiang estuary, Nanao island and Zhelin bay. Su5rfical and core sediment samples were collected from 46 and 13 stations respectively from June 2002 to June 2003. Sediments were dried at 50C in a closed fan-assisted oven, and then ground to fine powder using a mortar and sieved through a 250 m mesh. The sediments were digested with aqua- regia to determine the total amount of heavy metals. The "labile" fraction of heavy metals in sediment was leached with 1 N HCI, and the speciations of heavy metals in sediment were sequential extracted with BCR method. The heavy metal contents were measured using a ICP-AES (Perkin-Elmer 2000DV USA).The background of heavy metals in sediment makes a great contribution to distinguish the natural and anthropogenic resource of heavy metal, which was an appropriate reference level for evaluating the degree of heavy-metal contamination. The background of heavy metals in the coast sediment of eastern Guangdong province was determined with the pre-industry sediments that were selected in the substrate of core samplers. The result showed that the background of heavy metals were: Cd, 0.15u /g; Co, 8.40 g/g; Cr, 28.39 g/g; Cu, 19.22 g/g; Mn, 343.14 g/g; Ni, 14.91 g/g; Pb,32.87 g/g; Zn, 58.58;Fe,3.57%. Comparison with other sea areas, the background of Cu, Pb were high, which results from that eastern Guangdong province is rich in Cu, Pb mineral resources.The average contents of heavy metals in eastern Guangdong province were: Cd, 0.38ug/g; Co, 9.00ug/g; Cr, 38.20ug/g; Cu, 30.05ug/g; Mn, 622.66ug/g; Ni, 20.90ug/g; Pb, 43.65ug/g; Zn, 97.12ug/g; Fe, 3.63%. Comparison with other studies areas, which indicted that the average contents of Pb, Zn in eastern Guangdong province were high. The distribution of of Cd, Cr, Cu, Ni, Zn were that their average contents decreased from Shantou harbor to Nanao island, and increased slightly from Nanao island to Zhelin bay again. The highest average contents of Pb, Co, Mn were in Hanjiang estuary, which was different in distribution from other heavy metals. The correlation, cluster and enrichment factor analysis of heavy metals, calcium carbonate, total organic matter, silt and clay showed that Cd, Cr, Cu, Ni, Zn have the similar resource and geochemistry behavior, their distribution were determined by sewage discharge. However Pb, Co, Mn was not as same as above heavy metals in origins and geochemistry behavior. Atmosphere flux determined the distribution of Pb and that of Co, Mn was determined by redox potential.Based on the total contents of heavy metal, the pollution degree was assessed with three criterions. As a whole, the sediments was first-class sediments according to the criterions of sediments quality standard, and was uncontaminated according to the index of geoaccumulation, and was moderately contaminated according to the index of multi-ecological risk. However, the sediments of Shantou harbor was serious contaminated by Cu and Cd, according to the three criterions.The "labile" fraction of heavy meta...
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