中文关键词南方地区桉树水库泛黑沉积物扩散通量 英文关键词southern ChinaEucalyptusreservoirblackwatersedimentdiffusion flux

作者	单位	E-mail
朱雅	河海大学环境学院, 浅水湖泊综合治理与资源开发教育部重点实验室, 南京 210098	836674553@qq.com
李一平	河海大学环境学院, 浅水湖泊综合治理与资源开发教育部重点实验室, 南京 210098	liyiping@hhu.edu.cn
罗凡	广东省环境科学研究院, 广州 510045
李荣辉	广西水利科学研究院, 南宁 530023
黄列	广西水利科学研究院, 南宁 530023
程一鑫	河海大学环境学院, 浅水湖泊综合治理与资源开发教育部重点实验室, 南京 210098
蒋裕丰	南京河海科技有限公司, 南京 210016

中文摘要 桉树人工林区水库水体大面积泛黑引发的水质安全问题是目前关注的热点问题之一，我国南方地区尤其是广西南宁市90%以上的饮用水源水库周边都大量种植桉树，且很多都出现不同程度的水体泛黑现象.已有研究表明水库沉积物对上覆水Fe²⁺、Mn²⁺、S^2-和DOC的迁移转化过程起着重要作用，探究水体污染物在沉积物-水界面附近的分布特征与迁移规律对揭示库区泛黑机制具有重要意义.本研究利用柱状泥样分层分析方法和高分辨率原位被动采样技术，于2018年7~12月在我国南方典型泛黑水库天雹水库开展3次实验，分析沉积物中铁、锰、硫化物和有机质的分布特征及季节性变化规律，并重点研究泛黑期沉积物间隙水Fe²⁺、Mn²⁺、S^2-和DOC的剖面分布规律及迁移方向.结果表明：①桉树人工林区水库沉积物中铁和锰含量丰富，远超过全国土壤背景值.表层沉积物中铁、锰和TOC含量随季节同步增加，主要来源于水库周边桉树林区物质（残落物、腐解液和土壤颗粒）的输入与沉降；②桉树人工林区水库泛黑期沉积物间隙水中Fe²⁺（16.99 mg·L^-1）和DOC（36.80%）含量显著高于湖泛体系沉积物（12.15 mg·L^-1和10.78%），Fe²⁺/S^2-与Mn²⁺/S^2-比值均大于300，缺氧条件下沉积物中以铁锰氧化物的还原反应为主；③桉树人工林区水库沉积物中Fe²⁺扩散通量[27.4~33.5 mg·（m²·d）^-1]分别是太湖、阿哈水库和红枫湖的32.6、4.9和30.8倍，具有更强的Fe²⁺内源释放能力，且间隙水中Fe²⁺与DOC（r>0.904，P<0.01）显著正相关，沉积物中铁还原产物与有机质的络合反应是水库突发性泛黑的重要成因之一. 英文摘要 The safety of water quantity and quality caused by large-scale blackwater in reservoirs with Eucalyptus plantation is currently a point of great interest. Eucalyptus is largely planted in southern China, especially in Nanning, Guangxi, where more than 90% of the drinking water source reservoirs are surrounded by Eucalyptus, and different degrees of blackwater often occur in many reservoirs. Recent research has demonstrated that reservoir sediments play an important role in the migration and transformation of Fe²⁺, Mn²⁺, S^2-, and dissolved organic carbon (DOC) in the overlying water. It is of great significance to explore the distribution characteristics and migration rules of pollutants in the sediment-water interface to reveal the mechanism of blackwater in reservoirs. Experiments were carried out three times in a typical blackwater reservoir (Tianbao Reservoir) in southern China from July to December 2018. The distribution characteristics and seasonal variations of iron, manganese, sulfide, and organic matter in sediments were analyzed, focusing mainly on the profile distribution and migration direction of Fe²⁺, Mn^2+, S^2- and DOC in pore water during blackwater periods. The results showed that:① The content of iron and manganese in sediments of reservoirs with Eucalyptus plantation is high, far exceeding the background value of soil content in China. The content of iron, manganese, and total organic carbon (TOC) in the surface sediments increases simultaneously, mainly caused by the input and settlement of the material (litter, decomposed liquids. and soil particles) in the Eucalyptus forest around the reservoir. ② The concentration of Fe²⁺(16.99 mg·L^-1) and the content of DOC (36.80%) in pore water during the blackwater period are significantly higher than those in Taihu Lake during the black bloom (12.15 mg·L^-1, 10.78%). The mean concentrations of Fe²⁺ and Mn²⁺ are more than 300 times higher than that of S^2-, and the reduction conditions in the sediments are dominated by iron and manganese oxides. ③ The diffusion flux of Fe²⁺ is 27.4-33.5 mg·(m²·d)^-1, which is 32.6, 4.9, and 30.8 times higher than those of Taihu Lake, Aha Reservoir, and Hongfeng Lake, respectively. This implies strong Fe²⁺ release ability from sediments to the overlying water. As a positive correction exists between Fe²⁺ and DOC, the complex reaction between Fe²⁺ and organic matter is one of the most important causes of blackwater in reservoirs with Eucalyptus plantation.

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