Application of geochemical and stable isotopic tracers to investigate groundwater salinity in the Ochi-Narkwa Basin, Ghana

作者：Ganyaglo Samuel Y^*; Osae Shiloh; Akiti Tetteh; Armah Thomas; Gourcy Laurence; Vitvar Tomas; Ito Mari; Otoo Isaac A

来源：Hydrological Sciences Journal, 2017, 62(8): 1301-1316.

DOI：10.1080/02626667.2017.1322207

• geochemistry
• stable isotopes
• salinity sources
• Ghana

Rainwater, groundwater and soil-water samples were analysed to assess groundwater geochemistry and the origin of salinity in the Ochi-Narkwa basin of the Central Region of Ghana. The samples were measured for major ions and stable isotopes (O-18, H-2 and C-13). The Cl- content in rainwater decreased with distance from the coast. The major hydrochemical facies were Na-Cl for the shallow groundwaters and Ca-Mg-HCO3, Na-Cl and Ca-Mg-Cl-SO4 for the deep groundwaters. Groundwater salinization is caused largely by halite dissolution and to a minor extent by silicate weathering and seawater intrusion. Stable isotope composition of the groundwaters followed a slope of 3.44, suggesting a mixing line. Chloride profiles in the soil zone revealed the existence of salt crusts, which support halite dissolution in the study area. A conceptual flow model developed to explain the mechanism of salinization showed principal groundwater flow in the NW-SE direction.

• 出版日期2017