Pleistocene paleo-groundwater as a pristine fresh water resource in southern Germany--evidence from stable and radiogenic isotopes.
Pleistocene paleo-groundwater as a pristine fresh water resource in southern Germany--evidence from stable and radiogenic isotopes.
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DOI：
10.1016/j.scitotenv.2014.07.011
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发表时间：
2014-10
期刊：
影响因子：
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通讯作者：
R. van Geldern;Alfons Baier;Hannah L Subert;Sigrid Kowol;L. Balk;J. Barth
中科院分区：
文献类型：
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作者：
R. van Geldern;Alfons Baier;Hannah L Subert;Sigrid Kowol;L. Balk;J. Barth
浅层地下水含水层经常受到人为污染物或营养水平增加的影响。相比之下，较深的含水层可能保存着未受现代补给影响的原始古水。因此，它们代表着重要的水资源，但它们的补给历史往往是未知的。本研究对德国南部两个含水层的地下水进行了氢、氧稳定同位素组成分析。其中一个采样活动针对的是受现代降水积极补充的上层含水层，而第二个采样活动则针对受限制的深层Benkersandstein含水层。将两个含水层的地下水样品与当地的大气水线进行比较，探讨地下水补给的来源和条件。此外，通过氚和放射性碳分析确定了深层地下水的年代。稳定同位素和放射性成因同位素数据表明，在近代人类历史中，深含水层地下水不属于水文水循环的一部分。结果表明，该地区地下水年龄在~2万年以上，极有可能来自更新世冰期同位素耗尽的融水。今天，这个含水层的使用受到严格的管制，以保护原始的水。通过同位素地球化学手段明确确定这种不可再生的古水将有助于地方水务当局在可持续水管理的背景下为子孙后代制定和证明保护这些宝贵资源的措施。
Shallow groundwater aquifers are often influenced by anthropogenic contaminants or increased nutrient levels. In contrast, deeper aquifers hold potentially pristine paleo-waters that are not influenced by modern recharge. They thus represent important water resources, but their recharge history is often unknown. In this study groundwater from two aquifers in southern Germany were analyzed for their hydrogen and oxygen stable isotope compositions. One sampling campaign targeted the upper aquifer that is actively recharged by modern precipitation, whereas the second campaign sampled the confined, deep Benkersandstein aquifer. The groundwater samples from both aquifers were compared to the local meteoric water line to investigate sources and conditions of groundwater recharge. In addition, the deep groundwater was dated by tritium and radiocarbon analyses. Stable and radiogenic isotope data indicate that the deep-aquifer groundwater was not part of the hydrological water cycle in the recent human history. The results show that the groundwater is older than ~20,000 years and most likely originates from isotopically depleted melt waters of the Pleistocene ice age. Today, the use of this aquifer is strictly regulated to preserve the pristine water. Clear identification of such non-renewable paleo-waters by means of isotope geochemistry will help local water authorities to enact and justify measures for conservation of these valuable resources for future generations in the context of a sustainable water management.