Document Type : Original Article
Authors
1
Soil Science Department, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
2
Food and Drug Administration, Riyadh, Saudi Arabia
3
Soil and Water Science dept., Alexandria Univesity
Abstract
Millions Muslim people drink Zamzam groundwater in Saudi Arabia whether bottled or un-bottled. However, numerous studies reported that this water has been contaminated. This study focuses on the chemical and microbial analyses of 50 Zamzam water samples. The soluble ions, trace elements, total colony counts, total coliforms group, and E.coli were determined and compared with WHO standards. The obtained results indicated that the dissolved salts, soluble cations and anions, Pb, Cd, As, Zn, Cu, Ni, Co, Fe, Mn, Cr, PO43−, NO2-, Br-, F-, NH4+, and Li+ were within permissible limits for all samples. Yet, 2% of waters contain NO3- at unacceptable limits. The WQI reveal that 94% of the samples were excellent for drinking (class I). While the remaining was unsuitable due to total coliforms group contamination “class (V)”. Durov diagram suggest no clear facies and dominant water type can be noted. It indicates mixing processes of two or more different facies might be occurring in the groundwater system. The Gibbs’s diagram revealed that the groundwater quality is influenced by chemical weathering of rock-forming minerals. All studied waters were undersaturated with respect to halite, gypsum, fluorite, and anhydrite. However, they were saturated with respect to dolomite, calcite, and aragonite. The undersaturated minerals tend to dissolve and increase water salinity. A direct relationship between Zamzam water salinity and rainfall is recorded. In world dry period between years 1901-1950, the Zamzam water salinity recorded 4500 mg L-1; however, it decreased dramatically to reach 500 mg L-1 in the year 2015.
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