连续萃取法研究海湾养殖区沉积物中重金属形态

Research of Sequential Extraction Procedure for Heavy Metals in Sediments from Mariculture Area

以连续萃取法研究海湾养殖区沉积物中重金属(Cd,Cu,Pb,Zn)的形态,将重金属分离为酸溶态、还原态、有机质结合态、硫化物结合态和残渣态。分别采用基体匹配法和内标法消除高盐基体对电感耦合等离子体光谱法(ICP-OES)和质谱法(ICP-MS)分析结果的影响。对海洋沉积物标准物质分析结果表明,样品稀释后测定值与标准值一致。比较了本连续萃取法和BCR法对沉积物样品中重金属形态的提取结果,并考察了萃取剂的选择性。实验表明,本方法可用于有机质污染和富营养化环境沉积物中重金属形态分析,特别是有机质结合态和硫化物结合态的分析。

A sequential extraction procedure has been proposed for the evaluation of the speciation of heavy metals including Cd, Cu, Pb and Zn in sediments from maricuhure area, and the speciation of heavy metals was separated and defined as acid soluble fraction, reducible fraction, fraction bound organic matter, fraction bound sulfides and residual fraction. Matrix effects of high salinity on the determination of heavy metals in sediments were eliminated by matrix matching and internal standard methods when inductively couple plasma optical emission spectroscopy （ICP-OES） and mass spectroscopy （ICP-MS） were used, respectively. The results showed that the measured values of marine sediment reference materials were consistent with the standard values when the digestion solutions were determined after dilution. The extraction results of the propositional extraction procedure and European Community Bureau of Reference Program （BCR） procedure were compared and the selectivity of extractants was investigated. The preliminary studies indicated that this sequential extraction procedure was applicable for evaluating the speeiation of heavy metals in sediment with organic substances pollution and eutrophication, especially for fraction bound organic matter and fraction bound sulfides.