漓江上游青狮潭灌区干支渠沉积物重金属分布规律及来源解析

Distribution and Source Analysis of Heavy Metals in Sediments of Qingshitan Irrigation District in Lijiang River Basin

为了揭示漓江上游农业区域灌渠重金属含量及其分布规律,通过选取青狮潭水库西干渠及其支渠为研究对象,测定了干支渠表层沉积物(0~5 cm)的重金属含量,分析沉积物重金属的分布特征和污染现状,进行潜在生态风险评价,利用pearson相关性分析与正定矩阵因子分解法(PMF)分析重金属来源。结果表明,沉积物重金属含量在水稻生长的灌溉季节(平水期)和非灌溉季节(枯水期)平均值大小顺序均为Zn>Cr>Pb>Cu>As>Cd>Hg,干渠和支渠之间,灌溉季节和非灌溉季节之间沉积物重金属含量差异显著。灌渠沉积物的重金属潜在生态风险等级为强,Cd与Hg是主要污染物,不同季节和干支渠直接的重金属潜在生态风险等级差异。干支渠沉积物重金属来源包括工业污染源、农业污染源与城市(城镇)污染源,其中,农业污染源占主导,贡献率为42.45%,工业污染源与城市(城镇)污染源贡献率分别为33.86%与23.69%。

In order to reveal the content and distribution of heavy metals in agricultural areas of the Lijiang River Basin,the west main canal and its tributaries of Qingshitan Irrigation District are selected as the research objects in this paper.The content of heavy metals in the surface sediments(0~5 cm)of the main and its tributaries is determined,and the distribution characteristics and pollution status of heavy metals in sediments are analyzed.The potential ecological risk assessment is carried out.The pearson correlation analysis and positive definite matrix factor decomposition(PMF)are used to analyze the sources of heavy metals.The results show that the average contents of heavy metals in sediments in irrigation season and non-irrigation season are Zn>Cr>Pb>Cu>As>Cd>Hg,and the contents of heavy metals in sediments in main canals and tributaries,irrigation season and non-irrigation season are significantly different.The potential ecological risk of heavy metals in the sediments of irrigation canals is strong,Cd and Hg are the main pollutants,and the potential ecological risk levels of heavy metals in different seasons and direct tributaries are different.The sources of heavy metals in sediments of main and branch channels include industrial pollution sources,agricultural pollution sources and urban pollution sources.Among them,agricultural pollution sources accounts for 42.45%,industrial pollution sources and urban pollution sources accounts for 33.86%and 23.69%,respectively.