三峡库区(重庆-宜昌段)沉积物中钒的污染特征及生态风险评价

为全面了解三峡库区(重庆—宜昌段)干支流沉积物中钒的含量水平、空间分布、赋存形态、污染程度,在三峡库区采集水体沉积物样品67个,测定了沉积物中钒的含量及其化学赋存形态,并采用地积累指数法和潜在生态危害指数法进行分析和评价.结果表明:1三峡库区研究区范围内沉积物中钒的含量范围为89.4~175.2 mg·kg-1,平均值为123.7 mg·kg-1,略高于长江沉积物背景值;2库区沉积物中钒的空间分布特征主要呈现库区干流含量大于支流,干流下游沉积物中钒含量高于上游;3沉积物中钒含量的极值点出现在较发达县(区)附近,考虑其来源可能是人为源汇入;4库区沉积物中钒的赋存形态主要以残渣态为主,所占质量分数为80%~89%,并与总量呈现显著正相关关系;5沉积物中钒污染程度较小,潜在环境危害影响较弱.

Pollution Characteristics and Ecological Risk Assessment of Vanadium in Sediments of the Three Gorges Reservoir (Chongqing-Yichang Section)

In order to investigate the pollution characteristics of vanadium in sediments of the Three Gorges Reservoir (TGR), 67 sediment samples were collected from the section between Chongqing to Yichang in TGR. The concentration and chemical speciation of vanadium were measured and the spatial distribution of vanadium was discussed. Current pollution level of vanadium in TGR sediments was assessed by index of geoaccumulation and Häkanson ecological risk index. The results showed that:1the range of vanadium concentrations in TGR was 89.4-175.2 mg·kg^-1 and the average concentration was 123.7 mg·kg^-1, which was slightly higher than the background value in sediments of Yangtze River. 2the spatial distribution of vanadium in TGR sediments showed that vanadium concentrations in the mainstream of TGR were higher than those in tributaries and the vanadium contents in the sediments in downstream were higher than those in upstream in term of the mainstream of TGR. 3highest vanadium concentration was found in the sediment in a developed county, indicating that this high level of vanadium concentration was attributed to anthropogenic input. 4chemical forms of vanadium in sediments were mainly in residual state (80%-89%, mass fraction), which had a significant positive correlation with total concentrations in sediments. 5vanadium contamination degree and potential environmental risk in TGR sediments were weak.