中文摘要：

采用冷扩散法和连续萃取方法对珠江口桂山岛附近7个位点表层沉积物中酸可挥发性硫化物（AVS）、同步萃取重金属（SEM）和沉积物中重金属形态进行了研究.研究结果表明,表层沉积物中AVS含量较低,沉积物中重金属主要以残留态和硫化物结合态存在,其次为还原态、有机质结合态和少量弱酸提取态.Pearson相关分析表明,沉积物中SEM与Ca（r=0.677）、Al（r=0.668）和Fe（r=0.787）有显著正相关关系,而与有机碳（r=-0.908）有显著负相关关系,沉积物组分影响着重金属的生物毒性,SEM/AVS预测可能会过高估计重金属生态毒性.由150μmol.g-1〈（∑SEM-AVS）/fOC〈340μmo.lg-1,表层沉积物中重金属对底栖生物有潜在或慢性毒性作用.对沉积物样品中SEM结合特征研究表明,SEM-Cu主要为Cu弱酸提取态、还原态和硫化物结合态,另有部分有机质结合态和少量残留态;SEM-Pb和SEM-Ni主要为Pb和Ni残留态,同时还包括Pb和Ni全部弱酸提取态、还原态、有机质结合态和硫化物结合态;SEM-Zn主要为Zn弱酸提取态、还原态和硫化物结合态,另有少量的有机质结合态.

英文摘要：

The acid volatile sulfide （AVS）,simultaneously extracted metals （SEM） and chemical fractions of heavy metals in the surface sediments from 7 sites of the Guishan Island sea area in the Pearl River Estuary were studied by cold diffusion and sequential extraction. The concentrations of AVS were low in the surface sediments. The primary fractions of heavy metals mainly consisted of the residual fraction and the sulfide-bound fraction followed by reducible,organic matter bound fractions and a few weak acid soluble fractions. According to Pearson correlation analysis,significant positive correlation was observed among SEM with Ca （r=0.677）,Al （r=0.668）,and Fe （r=0.787）. However,a significant negative correlation was observed between SEM and organic carbon （r=-0.908）. These results indicated that sediment composition affected the biotoxicity of heavy metals,and the SEM/AVS prediction may overestimate the biotoxicity of heavy metals. Based on the values of 150 μmol·g-1（∑SEM-AVS）/fOC340 μmol·g-1 in sediment samples,heavy metals could induce potential or chronic toxicity to benthic organisms. Investigations of the binding characteristics of SEM revealed that SEM-Cu and SEM-Zn mainly included all of the weak acid soluble,reducible and sulfide-bound fractions,as well as a part of the organic matter bound fraction,yet SEM-Pb and SEM-Ni included all of the weak acid soluble,reducible,organic matter bound and sulfide-bound fractions,as well as a part of the residual fraction.