The origin of increased salinity in the Cambrian-Vendian aquifer system on the Kopli Peninsula, northern Estonia
The origin of increased salinity in the Cambrian-Vendian aquifer system on the Kopli Peninsula, northern Estonia
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DOI：
10.1007/s10040-004-0339-z
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发表时间：
2004-04
影响因子：
2.8
通讯作者：
E. Karro;A. Marandi;R. Vaikmäe
中科院分区：
文献类型：
--
作者：
E. Karro;A. Marandi;R. Vaikmäe
对塔林科普利半岛用于工业供水的寒武纪-旺迪亚承压含水层系统进行了 24 年来的监测，揭示了地下水化学成分的显着变化。由于大量抽水，抽取的地下水中 TDS 和主要离子浓度相对较快地增加了 1.5 至 3.0 倍。寒武系-旺迪系地下水溶解负荷的主要来源是围岩的淋滤和饱和带中发生的其他地球化学过程。下伏的结晶基底由上部风化和裂隙部分的含盐地下水组成，并与上覆的寒武纪-旺迪亚含水层系统水力相连，是第二个重要的离子源。断裂的基底及其粘土风化壳含有 Ca-Cl 型地下水，其特点是 TDS 值较高（2-20 g/L）。集约化抽水加速了地下水的交换并增加了抽水的影响范围。地下水的化学和同位素研究表明，来自结晶基底的旧微咸水的贡献越来越大，并排除了海水侵入含水层的潜在影响。
Monitoring of the confined Cambrian-Vendian aquifer system utilised for industrial water supply at Kopli Peninsula in Tallinn over 24 years reveals remarkable changes in chemical composition of groundwater. A relatively fast 1.5 to 3.0-fold increase in TDS and in concentrations of major ions in abstracted groundwater is the consequence of heavy pumping. The main sources of dissolved load in Cambrian-Vendian groundwater are the leaching of host rock and the other geochemical processes that occur in the saturated zone. Underlying crystalline basement, which comprises saline groundwater in its upper weathered and fissured portion, and which is hydraulically connected with the overlying Cambrian-Vendian aquifer system, is the second important source of ions. The fractured basement and its clayey weathering crust host the Ca-Cl type groundwater, which is characterised by high TDS values (2–20 g/L). Intensive water abstraction accelerates the exchange of groundwaters and increases the area of influence of pumping. Chemical and isotopic studies of groundwater indicate an increasing contribution of old brackish water from the crystalline basement and rule out the potential implication of an intrusion of seawater into aquifer.