Lan Xiao-Long, Ning Zeng-Ping, Xiao Qing-Xiang, Huang Zheng-Yu, Liu Yi-Zhang, Xiao Tang-Fu, Zhao Yan-Long, Wu Shi-Liang
State Key Laboratory of Environmental Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Huan Jing Ke Xue. 2018 Feb 8;39(2):748-757. doi: 10.13227/j.hjkx.201705288.
In order to evaluate the pollution status, possible sources, and bioavailability of heavy metals (As, Cd, Pb, Sb, Zn, and Tl), 33 surface sediments were collected from Longjiang River, Southern China. The total concentrations and potential bioavailable concentrations of the heavy metals were analyzed using ICP-MS. Enrichment factors (EFs), Pearson correlation analysis, and principal component analysis (PCA) were used to further assess their pollution degree and potential sources. Results showed that the surface sediments of Longjiang River have been suffering heavy metal (As, Cd, Pb, Sb, and Zn) pollution to different degrees. The maximum concentrations of As, Cd, Pb, Sb, and Zn were 67.0, 7.42, 227, 229, and 807 mg·kg, respectively, while the Tl concentration were very low, with little variation. Moreover, the polluted sites were mostly located in the mid-lower of the main stem and in tributaries (Dongxioajiang and downstream of Dahuanjiang), and the pollution degree of the heavy metals, in a descending order, were Cd > Sb > Zn > Pb > As > Tl. Pearson correlation analysis and PCA indicated that As, Cd, Pb, Sb, and Zn predominantly originated from anthropogenic inputs, including nonferrous metal mining and smelting, municipal sewage, and agricultural activities, and Tl mostly derived from natural rock weathering. The bioavailability of heavy metals in the sediments tended to be controlled by their sources. The percentages of bioavailable heavy metals (As, Cd, Pb, Sb, and Zn) in the highly anthropogenic impacted areas (the mid-lower of the main stem and downstream of Dongxiaojiang tributary) were also high, with the average percentages of bioavailable As, Cd, Pb, Sb, and Zn of 26%, 51%, 49%, 38%, and 47%, respectively. High EF values and high bioavailable percentages of heavy metals easily and greatly cause high ecological risk of Longjiang River.
为了评估重金属（砷、镉、铅、锑、锌和铊）的污染状况、可能来源及生物有效性，在中国南方的龙江采集了33个表层沉积物样本。采用电感耦合等离子体质谱仪（ICP-MS）分析了重金属的总浓度和潜在生物可利用浓度。利用富集因子（EFs）、皮尔逊相关分析和主成分分析（PCA）进一步评估其污染程度和潜在来源。结果表明，龙江表层沉积物已受到不同程度的重金属（砷、镉、铅、锑和锌）污染。砷、镉、铅、锑和锌的最大浓度分别为67.0、7.42、227、229和807mg·kg，而铊的浓度很低，变化很小。此外，污染位点大多位于干流中下游及支流（东小江和大环江下游），重金属污染程度由高到低依次为：镉＞锑＞锌＞铅＞砷＞铊。皮尔逊相关分析和主成分分析表明，砷、镉、铅、锑和锌主要来源于人为输入，包括有色金属采矿和冶炼、城市污水及农业活动，而铊主要来源于天然岩石风化。沉积物中重金属的生物有效性往往受其来源控制。在受人为影响较大的区域（干流中下游和东小江支流下游），生物可利用重金属（砷、镉、铅、锑和锌）的百分比也较高，生物可利用砷、镉、铅、锑和锌的平均百分比分别为26%、51%、49%、38%和47%。高富集因子值和高生物可利用百分比的重金属容易且极大地导致龙江的高生态风险。
