贵州阿哈湖溶解态稀土的垂向分布及形态特征  

Vertical Distributions and Speciation of Dissolved Rare Earth Elements in Aha Lake,Southwestern China

作　　者：王思梦[1] 李军[1] 李勇[1] 朱兆洲[1] 

机构地区：[1]天津师范大学天津市水资源与水环境重点实验室,天津300387

出　　处：《中国稀土学报》2016年第4期494-503,共10页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金项目(40803002;41172315);天津市应用基础及前沿计划项目(14JCYBJC22400)资助

摘　　要：以中国西南季节性缺氧湖泊阿哈湖为主要研究对象,采用液-液萃取及ICP-MS测试技术,对湖泊不同深度水体中稀土元素进行分析。研究结果表明:随着阿哈湖水体深度增加,从表层至湖上层下部溶解态稀土浓度急剧升高,从湖上层底部至温跃层顶部稀土浓度快速降低,从温跃层上部至湖下层上部溶解态稀土浓度逐渐降低。湖泊颗粒物表面有机碳的矿化作用是造成溶解态稀土在湖上层浓度急剧升高的主要原因,胶体的絮凝作用使溶解态稀土在湖上层底部至温跃层顶部浓度急剧下降,在温跃层上部至湖下层上部水体中,由于新生成的MnO_2吸附作用使溶解态稀土浓度持续下降。形态模拟结果显示,溶解态稀土主要是以稀土有机结合态和稀土碳酸盐结合态两种形式存在。稀土有机络合物占总溶解态的比例遵循以下规律:湖上层>温跃层>湖下层;LREE-DOC>MREE-DOC>HREE-DOC。The concentrations of dissolved rare earth elements（ REEs） were determined in water column of AhaLake with seasonal deep-water anoxia in southwestern China,by inductively coupled plasma mass spectrometry（ ICP-MS） after preconcentration with solvent extraction and back-extraction. The results showed that the concentrations of dissolved REEs increased sharply from surface water to the lower epilimnion. That was mainly caused by the mineralization of organic carbon on the surface of suspended particulate matters（ including large-size colloids）.The coagulation of colloids made dissolved REEs concentration decreasing markedly from bottom of epilimnion to uppermost layer of metalimnion. The dissolved REEs concentrations decreased gradually with increasing water depths from upper metalimnion to uppermost layer of hypolimnion. The decrease of concentration was the result of adsorption by the freshly MnO2. The calculations indicated that the dominant species were Ln-DOC and Ln-DIC in solutions from Aha Lake. The percentage of Ln-DOC account for dissolved metal followed the order： eplimnion metalimnion hypolimnion and LREE-DOC 〉MREE-DOC 〉HREE-DOC.

关 键 词：阿哈湖 水体剖面 溶解态稀土 浓度 形态 

分 类 号：X142[环境科学与工程—环境科学] P592[天文地球—地球化学]