Date of Award

11-2014

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr. Ruwaya Alkendi

Second Advisor

Dr. Khaled A. EI-Tarabily

Third Advisor

Dr. Zeinelabidin E. Rizk

Abstract

The groundwater is the most important source of water in the Sultanate of Oman. Accordingly, the Oman Government has paid great attention commensurate with the importance of water resource in terms of their sources, quality, and ways to rationalize consumption to remain under the term of sustainability and validity of present and future generations. This study was conducted in Al Buraymi at Mahdah State in AI-Zoroub area targets a groundwater quality for 20 wells in private farms. The water samples were taken from these wells and subjected to analysis for microbial and geochemical aspects. For this analysis, the assorted devices and instruments were implemented. Additionally, to focus on the possible sources of pollution and the range of competence for the human user or livestock and agriculture of this water, the international guideline measures were used for compression.

Based on investigations from a group of chemical and biological analysis; it turns out that this water contained varying proportions of salts and dissolved minerals. These results also build on the proportions of dissolved salts which showed different types of water in these wells which are mostly fresh (magnesium bicarbonate) in ten wells, brackish (magnesium chloride) in six wells and saline (sodium chloride) in four wells.

The dominant water type (magnesium bicarbonate) resulted from the fresh water in the upper aquifer, which recharged from northeastern catchment areas of Mahadah, Wadi Al Jizi, and Wadi Hamad. Moreover, it was found that the abundance of the major cation ions in groundwater is in the following order: Na+ > Mg2+> Ca2+> K+, whereas the abundance of the major anion ions in groundwater is in the following order: Cl-> HCO3-> SO4-> NO3-. These distribution is effected by salinization phenomena (ion exchange), mixing of saline water in the deep aquifer with fresh water and by anthropogenic sources.

The building at the expense of sodium adsorption ratio (SAR) found that 65% of the wells are located within the category of hazardous water at least for sodium ion and medium salinity rate. So they are safe for agricultural use except for well no (8) located in the category of high salinity.

On the other hand, the results showed microbial water containing high levels of coliform bacteria and E.coli species in nine wells. Compared to WHO guidelines, not all 20 wells that I have investigated are suitable for human use without treatment, and 70% of them are not suitable for animal use, but in contrast, all wells are suitable for agricultural use.

During the term of microbial source tracking method (MST) that applied on 9Escherichia coli (E.coli) samples used 16SrRNA, which blasted in the NCBI; sequences of these samples were identified by comparison with the GenBank database used BLAST searches. It was found that all isolated E.coli were homologous with isolated single E.coli species (E.coli K-12 substr - MG 1655 strain) which first identified in the faeces of human. According to filed survey and investigation, the main cause of E.Cole in the groundwater is may be septic tank and animal manure, which is very close to these wells, or the well heads are not completely sealed, which would allow contaminants to enter the well.

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