富集因子法中参比元素的选取方法——以元江底泥中重金属污染评价为例

富集因子法中参比元素的选择对目标元素富集程度评价及源解析结果有至关重要的影响,盲目选用可能会导致偏颇或错误的结论,但目前鲜有针对参比元素的选择所进行的探讨.本文以元江沉积物中重金属元素污染水平评价及来源解析为例,详细介绍了运用顺序提取法、相关分析法、聚类分析法等化学分析和数理统计相结合并联系研究区域地球化学背景、产业分布及元素特性确定参比元素的方法.并采用所选出的参比元素进行富集因子法分析,将所得重金属污染等级评价结果及重金属来源的推论与地积累指数法对重金属污染等级评价的结果和以因子分析法对重金属溯源的推论相比较.结果表明,利用相关分析和顺序提取等方法选择参比元素是可靠可行的.

Selection of a reference element for enrichment factor: A case study on the pollution evaluation of heavy metals in the sediment of Yuan River

Enrichment Factor (EF) is widely used in heavy metal pollution evaluation and source apportionment. Selection of an appropriate reference element in EF method is very important. An arbitrary selection without a specific analysis may lead to biased or incorrect conclusions. However, selection process of a reference element rarely appeared in most papers. Our paper took the pollution evaluation and source identification of heavy metals in the sediment of Yuan River as an example to demonstrate the selection method of a reference element. We used a combination of sequential extraction, correlation analysis, cluster analysis, as well as investigation of the geochemical background and industrial discharge to determine an appropriate reference element from the metal elements most frequently used as reference elements. Then, we used geo-accumulation index and factor analysis to verify the EF conclusions. The comparison showed that the selected reference element was fairly adequate and the selection process was reliable. Thus, a systematic method combining statistical analysis and chemical sequential extraction is suggested for selecting the reference element in EF method.