Tracing the Seepage of Subsurface Sinkhole Vent Waters into Lake Huron Using Radium and Stable Isotopes of Oxygen and Hydrogen
Tracing the Seepage of Subsurface Sinkhole Vent Waters into Lake Huron Using Radium and Stable Isotopes of Oxygen and Hydrogen
复制标题
DOI：
10.1007/s10498-015-9286-7
复制
发表时间：
2016-08-01
影响因子：
1.6
通讯作者：
Biddanda, B. A.
中科院分区：
文献类型：
--
作者：
Baskaran, M.;Novell, T.;Biddanda, B. A.
地下水和地表水之间的水交换可能改变地表沃茨的水质，从而影响其生态系统。最近有记录表明，休伦湖的三个天坑喷口（埃尔卡洪、中岛和孤立）排放出高浓度硫酸盐和氯化物、低浓度硝酸盐和氧气的缺氧地下水。在这项调查中，我们收集和分析了一套水样本从这三个天坑喷口和湖水样本从休伦湖Ra，氡-222，稳定同位素的氧和氢，以及其他辅助参数。这些测量是在这种独特的环境中进行的首次测量。Ra的活度比湖水高1 ~ 2个数量级。一些底部湖水样本的同位素特征表明，在距离这三个喷口较远的地方存在微渗漏的证据。三角洲D与三角洲O-18的关系图表明，由于不同水团的混合和/或由于一些地下化学反应，全球流星线存在偏差。使用Ra同位素比率，我们估计了喷口沃茨从喷口底部到顶部的渡越时间（即，沉积物-水界面）为4-37天。需要对放射性和稳定同位素的分布进行更系统的研究，以评估休伦湖和其他五大湖系统中微渗漏的普遍性。
Exchange of water between groundwater and surface water could alter water quality of the surface waters and thereby impact its ecosystem. Discharges of anoxic groundwater, with high concentrations of sulfate and chloride and low concentrations of nitrate and oxygen, from three sinkhole vents (El Cajon, Middle Island and Isolated) in Lake Huron have been recently documented. In this investigation, we collected and analyzed a suite of water samples from these three sinkhole vents and lake water samples from Lake Huron for Ra, radon-222, stable isotopes of oxygen and hydrogen, and other ancillary parameters. These measurements are among the first of their kind in this unique environment. The activities of Ra are found to be one to two orders of magnitude higher than that of the lake water. Isotopic signatures of some of the bottom lake water samples indicate evidences for micro-seeps at distances farther from these three vents. A plot of delta D versus delta O-18 indicates that there are deviations from the Global Meteoric Line that can be attributed to mixing of different water masses and/or due to some subsurface chemical reactions. Using the Ra isotopic ratios, we estimated the transit times of the vent waters from the bottom to the top of the vent (i.e., sediment-water interface) to be 4-37 days. More systematic studies on the distribution of the radioactive and stable isotope studies are needed to evaluate the prevalence of micro-seeps in Lake Huron and other Great Lakes system.