Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.scitotenv.2017.07.199
Title (Primary) Geochemical processes controlling groundwater quality under semi arid environment: A case study in central Morocco
Author Karroum, M.; Elgettafi, M.; Elmandour, A.; Wilske, C.; Himi, M.; Casas, A.
Journal Science of the Total Environment
Year 2017
Department FLOEK
Volume 609
Page From 1140
Page To 1151
Language englisch
Keywords Groundwater salinisation; Cl/Br; F; Environmental isotope; Morocco
UFZ wide themes RU2;
Abstract Bahira plain is an important area for Morocco due to its agriculture and mining activities. Situated in a sub-arid to arid climate, this plain hosts an aquifer system that represents sequences of carbonates, phosphates, evaporates and alluvial deposits. Groundwater flows from Ganntour plateau (recharge area) to the basin-fill deposits and Zima Lake and Sed Elmejnoun where water evaporates. The objective of this study was to characterize the chemical properties of the groundwater and to assess the processes controlling the groundwater's chemistry. We can divide water samples into three hydrochemical water groups: recharge waters (Ca/Mg–HCO3), transition zone waters (Ca–HCO3–SO4/Cl) and discharge waters (Na-Cl/SO4). Accordingly, compositions of waters are determined by the availability of easily soluble minerals like calcite (Ca–HCO3 dominant), halite (Na–Cl dominant) and gypsum (Ca–SO4 dominant). Cl/Br ratios show that Cl concentration increases from dissolution of natural halite. When groundwater is affected by extreme evaporation Cl/Br ratios may increase up to 1900. High fluoride concentrations are associated with low Ca2 + concentrations (< 100 mg/L). That means when recharge waters enter the aquifer, it starts dissolving fluorite since the Ca2 + concentration is low. Once groundwater becomes saturated with Ca2 +, the immobilization of fluoride is occurring by precipitation of fluoride-rich minerals like fluoro-apatite. According to the environmental isotope (18O and 2H) analyses, they are three potential processes affecting groundwater: 1. Evaporation as verified by low slope value, 2. Water-rock interaction, 3. admixture of waters showed different stable isotope compositions and salinities.
Persistent UFZ Identifier
Karroum, M., Elgettafi, M., Elmandour, A., Wilske, C., Himi, M., Casas, A. (2017):
Geochemical processes controlling groundwater quality under semi arid environment: A case study in central Morocco
Sci. Total Environ. 609 , 1140 - 1151