| Popis: |
The assessment of the origin of water that is allocated both for people and for irrigation in the eastern part of the Mitidja plain was carried out making use of geochemical and isotopic tools (18O, 2H and 3H). Both hydrochemical and isotopic information gathered for eastern Mitidja alluvial aquifer were used for the sake of assessing the mechanisms controlling groundwater chemistry. This allowed one to identify: (i) the natural or the anthropogenic processes that control groundwater quality, (ii) the origin of groundwater and when its recharge occurs. The work involved sampling campaigns, in situ measurements, and analyses of ions, heavy metals and water isotope content. Results showed a fair overall chemical quality of waters, since the assessment of water quality using water quality index (WQI) revealed that 90 % of the groundwater samples are good. Mitidja’s groundwaters fall into the Cl−SO4−Ca water type, that is mainly induced by water-rock interactions (dissolution of evaporites). The concentrations in Fe, Mn, Ni and Cd for some of the samples were found higher than the prescribed limits recommended by the World Health Organization. Isotopes indicate that groundwater is young since it originates from direct infiltration of precipitation that is mostly induced by Mediterranean atmospheric disturbances. |
