Kouli_etal_2008_Groundwater modelling_BOOK.pdf - Pantelis ...

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A. Akber, A. Mukhopadhyay, E. Azrag et al.
(e)
Figure 8. Cross-plot of nitrate-nitrogen concentration above 15 mg/L against (a) total dissolved solid
contents; (b) sodium concentration; (c) calcium concentration; (d) potassium concentration; and (e)
chloride concentration for the Kuwait Group aquifer.
present time) or a combination of the above (see Fig. 2c). The generally lower nitrate
concentration in the Dammam Formation aquifer and lack of correlation with the major
cations suggest absence or lower concentrations of nitrate bearing minerals in this aquifer
(Fig. 2d). A rather indirect evidence of the mineralogical source of nitrate in the groundwater
of Kuwait is the presence of some nitratine and trace quantity of niter in the surface soil in
Umm Er-Rimmam area as indicated by the X-Ray diffraction (XRD) patterns of these
materials (Figs. 10a and 10b) that might have either been the results of atmospheric
precipitation in this arid environment or derivation from the erosion of the Precambrian
Shield in Saudi Arabia. The cross-plot of δ 18 O and δ 34 S (Fig. 11) and Table 2 indicate that
δ 34 S values in groundwater of Kuwait is very similar to that of marine sulfates (in the range of
10 0 / 00 to 30 0 / 00 ; Botoman and Faure, 1976) and it is most likely that the source of sulfur in
groundwater is sedimentary sulfate minerals, e.g., gypsum (CaSO 4 . 2H 2 O) and anhydrite
(CaSO 4 ) that are known to be present in the sedimentary sequence of the study area. This is
an indirect evidence of derivation of some of the components of groundwater through
solution of minerals in the aquifer. It is further interesting to note that on the basis of δ 18 O and
δ 34 S values, it is difficult to distinguish wastewater from the groundwater in Kuwait.