Spatial distribution and chemical speciation of some potentially toxic elements in Qena Governorate groundwater, Egypt | ||
| Egyptian Journal of Chemistry | ||
| Volume 66, Issue 11, November 2023, Pages 137-150 PDF (1.18 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejchem.2023.188533.7488 | ||
| Authors | ||
| Hossam Abd-Elrazak Bahlol1; Mostafa Kamel2; El-Montser Seleem2; Alaa Mostafa3; Salman A. Salman* 4 | ||
| 1ATOS Pharma (SEKEM Group), Egypt | ||
| 2Faculty of Science, Al-Azhar University, Assiut Branch, Egypt | ||
| 3Faculty of Science, Al Azhar University, Assuit Branch, Egypt | ||
| 4Geological Sciences Dept., Inorganic Chemical Industries and Mineral Resources Research Division, National Research Centre | ||
| Abstract | ||
| Potentially toxic elements (PTEs) distribution and speciation follow up become one of the most challenging issues in the last decades owing to their hazardous health impact. The element’s species determines its toxicity, mobility, bioavailability and treatment possibility. This study focuses on the distribution and speciation of PTEs in Qena Governorate Groundwater by using GIS, MINTEQ and chemical techniques. Twenty-eight samples were collected and chemically analyzed according to standard methods. The concentrations of Fe, Mn, As, Cd, Cr, Ni and Pb were 25.95, 12.25, 8.07, 1.92, 52.35, 19.52 and 7.2 µg/L, respectively. Geochemically, the aquifer environment is reducing as appeared from negative value of Oxidation-reduction potentiality. Water-rock interaction is prevailing in this area with forward ion exchange reactions. Based on WHO specifications for drinking water, the studied samples have acceptable concentrations of Fe and Ni, but some samples have undesirable levels of Mn, As, Cd, Cr and Pb. The speciation model indicated that the studied elements occur as (HAsO4)-2, Cd+2, Cr(OH)3, PbCO3, Ni+2, Fe(OH)2+. These species are mostly of low toxicity and aquifer chemical conditions favor the co-precipitation of elements with iron hydroxides. Even though, the water can be used safely for irrigation with respect to PTEs. The main problem facing the use of this water for irrigation is the salinity (EC > 2250 µS/cm), in 71% of the studied samples. Finally, understanding the PTEs speciation in water will help comprehending the mobility, bioavailability and health hazards. | ||
| Keywords | ||
| Arsenic; Speciation; PTEs; Groundwater; Modelling; Qena | ||
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