Assessment of the Hydrogeochemical Processes Affecting Groundwater Quality in the Eocene Limestone Aquifer at the Desert Fringes of El Minia Governorate, Egypt
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- 作者：Reda G. M. Ibrahim ; W. Berry Lyons
- 关键词：Surface–groundwater relations ; Geochemical evolution ; Hydrogeochemical processes ; Stable isotopes ; El Minia Governorate ; Egypt
- 刊名：Aquatic Geochemistry
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：23
- 期：1
- 页码：33-52
- 全文大小：
- 刊物类别：Earth and Environmental Science
- 刊物主题：Geochemistry; Hydrology/Water Resources; Hydrogeology; Water Quality/Water Pollution;
- 出版者：Springer Netherlands
- ISSN：1573-1421
- 卷排序：23
文摘
El Minia Governorate is within the Nile Valley and is surrounded by the Eocene limestone plateaus from the east and west. The present study focuses on the hydrogeochemistry of the Eocene limestone aquifer in both the eastern and western desert fringes of El Minia. Thirty groundwater samples from the Eocene aquifer (east and west of the Nile) and seven samples from post-Eocene aquifers in this area were analyzed to assess the groundwater geochemistry, isotopic compositions and the subsurface hydrology. Samples obtained from depths of 24–120 m were measured for major components, nutrients, oxygen-18, deuterium and carbon-13. The groundwater TDS (total dissolved solids) concentrations ranged from 530 to 2788 and 453 to 1903 mg/l at the western and eastern desert fringes, respectively. Values of Eocene aquifer water δ18O ranged from −8.31 to −0.44 and −2.07 to 0.55 ‰, and those of water δD ranged from −63.6 to −2.32 and −9.03 to 5.03 ‰ for the Eocene aquifer at the western and eastern side, respectively. Chemical analysis shows that the main chemical facies of the Eocene water are Ca–Mg–HCO3 and Ca–SO4. The chemical and isotopic data show that water–rock interaction (calcite dissolution and silicate weathering) and mixing between different water types control the major ion chemistry of Eocene aquifer water. The chemical composition of Eocene water has also evolved by evaporation and ion exchange. The present study indicates the need for regional chemical and isotopic study for the Eocene aquifer along the Nile Valley region to delineate the sources of recharge to this important aquifer.