• 关键词：重金属污染  河床沉积物  污染程度评价  生态风险  健康风险  澧水

• 基金项目：湖南省高校科技创新团队支持计划项目（2014）；国家自然科学基金（No.41073095）

• 曾等志
• 1. 湖南师范大学资源与环境科学学院, 长沙 410081;2. 湖南师范大学环境重金属污染机理与生态修复重点实验室, 长沙 410081

• 彭渤
• 1. 湖南师范大学资源与环境科学学院, 长沙 410081;2. 湖南师范大学环境重金属污染机理与生态修复重点实验室, 长沙 410081

• 张坤
• 1. 湖南师范大学资源与环境科学学院, 长沙 410081;2. 湖南师范大学环境重金属污染机理与生态修复重点实验室, 长沙 410081

• 方小红
• 1. 湖南师范大学资源与环境科学学院, 长沙 410081;2. 湖南师范大学环境重金属污染机理与生态修复重点实验室, 长沙 410081

• 谭长银
• 1. 湖南师范大学资源与环境科学学院, 长沙 410081;2. 湖南师范大学环境重金属污染机理与生态修复重点实验室, 长沙 410081

• 匡晓亮
• 1. 湖南师范大学资源与环境科学学院, 长沙 410081;2. 湖南师范大学环境重金属污染机理与生态修复重点实验室, 长沙 410081

• 吴蓓娟
• 1. 湖南师范大学资源与环境科学学院, 长沙 410081;2. 湖南师范大学环境重金属污染机理与生态修复重点实验室, 长沙 410081

• 涂湘林
• 中国科学院广州地球化学研究所, 广州 510640

• 摘要：利用等离子质谱仪（ICP-MS）对澧水入湖段河床沉积物重金属含量进行分析测定，并对沉积物重金属污染程度进行了评价.结果表明，澧水入湖沉积物重金属Cd含量较高，超出土壤背景值3.5~15.6倍，超标率达100%.地累积指数评价结果显示，Cd处于中度污染水平，重金属污染程度从高到低为：Cd > Cu > Ni > Mn > Zn > Co > Pb > Cr > V.潜在生态风险评价结果显示，沉积物Cd的生态风险指数RI值在84.3~230之间，表现出很强的生态风险.重金属生态风险排序为：Cd > Cu > Ni > Pb > Co > Cr > V > Mn > Zn，且沉积物重金属Cd对潜在生态风险指数RI值的贡献率最大.健康风险评价结果显示，重金属Mn、V、Pb、Cr、Cu、Co、Zn、Ni、Cd等均没有显著的非致癌风险，儿童致癌风险比成人大1.3~5.6倍，其中，重金属Cr、Co可对儿童和成人构成潜在致癌风险.重金属Cd、Pb、Zn可能主要来自于工矿排放等人为带入，而V、Cr、Mn、Co、Ni、Cu等重金属可能主要来自流域基岩的自然风化、侵蚀等地表作用.流域重金属污染防治应主要针对Cd、Cr、Pb、Zn等重金属污染而进行.

• Abstract：Concentrations of heavy metals in bed sediments from inlet areas of the Lishui River to the Dongting Lake were analyzed using ICP-MS, and heavy metal contamination was evaluated. The results showed that the sediments contained very high contents of Cd which were 3.5 to 15.6 times higher than its background values in the Chinese average soil. Almost 100% of the sediment samples contained such high contents of Cd. Evaluation by Geoaccumulation Index (I_geo) suggested that the bed sediments were moderately contaminated by Cd. The contamination degrees for heavy metals was in the order of Cd > Cu > Ni > Mn > Zn > Co > Pb > Cr > V. The assessment by Hakanson potential ecological risk index (RI) showed that Cd in sediments had RI values from 84.3 to 230, indicating a strong potential ecological risk. The order of potential ecological risk degrees for heavy metals assessed by RI values was Cd > Cu > Ni > Pb > Co > Cr > V > Mn > Zn, within which Cd contributed the highest proportion to the RI values. Health risk assessment showed that Mn, V, Pb, Cr, Cu, Co, Zn, Ni and Cd in sediments are carcinogenic to people exposed to them. The possibility of cancer pathogeny for child is 1.3 to 5.6 times higher than for adult. Among these metals, Cr and Co in sediments may be carcinogenic for both child and adult. Principal component analysis and Pearson correlation among heavy metals suggested that Cd, Pb and Zn in sediments may be contributed mostly from anthropogenic activities such as Pb-Zn ore mining activities in upper river areas, while V, Cr, Mn, Co, Ni and Cu in sediments may be mostly from natural processes such as rock weathering throughout the watershed. Therefore, a great attention on contamination by metals Cd, Cr, Pb and Zn should be paid for environmental protection for the Lishui watershed.

• Key words：heavy metal contamination  river bed sediment  heavy metal contamination assessment  ecological risk assessment  health risk assessment  Lishui River

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