基于地累积向量模型的湖泊沉积物重金属污染评价

Heavy Metal Pollution Evaluation Model of Lake Sediment Based on Geo-accumulation Vector Theory

由于矿物质组成的不均匀性,沉积物中重金属的背景值往往具有不确定性,而传统的地累积指数模型难以处理这类具有不确定性的重金属污染评价问题。基于不确定性分析理论,对传统的地累积指数进行改进,构建了地累积向量模型。对洞庭湖荆江口段沉积物的重金属污染评价结果表明,与传统地累积指数模型相比,地累积向量模型在重金属污染的不确定性分析与综合评价方面均有显著优势;洞庭湖荆江口段的沉积物重金属污染等级为"偏中污染",且关键污染因子为镉、汞。

For the heterogeneity of the minerals components,the background value of the heavy metal in sediment often has uncertainties.However,the conventional geo-accumulation index（GI）model cannot deal with this uncertainty in heavy metal pollution evaluation.To solve this problem,an improvement on the conventional GI theory is made,and a new geo-accumulation vector（GV）is established based on the uncertainty analysis theory.The application of GV in the heavy metal pollution assessment of Jingjiangkou section of Dongting Lake shows that compared with the conventional GI,GV has better capacities in the uncertainty analysis and comprehensive pollution evaluation;In the Jingjiangkou section of Dongting Lake,the sediment is ＂uncontaminated to moderately contaminated＂ by heavy metals,and the key risk factors are cadmium and mercury.