Microbial and Chemical Pollution of Water-Wells Relative to Sewage Effluents in Oman

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Authors:
Saif N. Al-Bahry, Sultan Qaboos University, Oman
Ibrahim Y. Mahmoud, University of Nizwa, Oman
Salma K. Al-Musharafi, Sur Applied College of Sciences, Oman
Intisar S. Al-Gharibi, Ministry of Regional Municipality and Water Resources, Oman
Nasra K. Al-Harthy, Ministry of Environment and Climate Affairs, Oman
Halima A. Al-Zadjali, Ministry of Environment and Climate Affairs, Oman
Email: snbahry@squ.edu.om
Published: September 2014
https://doi.org/10.22492/ijsee.1.1.03

Citation: Al-Bahry, S. N., Mahmoud, I. Y., Al-Musharafi, S. K., Al-Gharibi, I. S., Al-Harthy, N. K., et al. (2014). Microbial and Chemical Pollution of Water-Wells Relative to Sewage Effluents in Oman. IAFOR Journal of Sustainability, Energy & the Environment, 1(1). https://doi.org/10.22492/ijsee.1.1.03


Abstract

During the last four decades in Oman there has been a rapid increase in the population, construction of housing, heavy industry and also an increase in agri- culture. This rapid growth shows no signs of abatement. This has led to an ever in- crease in water demand. Based on these facts, the existing methods of sewage water treatment and chlorination process is not effective in eradicating microbial contamination. In this study, the reuse of sewage effluent was one of the major causes of underground water pollution. Cracked septic tanks, cesspits, fertilizers and recycled treated sewage effluent (TSE) also added to underground water pollution. Excessive use of underground water due to water shortage led to salinization of the wells. A total of 276, 305 and 290 water-wells were sampled in 1995, 2000 and 2010 respectively for biological and physiochemical water contamination in Muscat, Oman. Relative to that, 300 samples of TSE were taken from four main sewage treatment plants (STPs). These samples were analyzed and compared with well-water samples. The analyses involved electrical conductivity, total dissolved solid (TDS), iron concentration, heavy metals, trihalomethanes (THMs), nitrate NO3 and microbial contamination. The dominant heavy metals in wells and TSE were Ni and Zn. In well- water, NO3, TDS and microbial count were high. The above parameters declined significantly in 2010 because of heavy rain. Heavy metals, THMs and nitrates in some wells exceeded maximum permissible level even after the 2010 declined. Multiple antibiotic resistant bacteria (MARBs) were tested for 16 antibiotics and were found in both TSE and well-water. Resistance of Escherichia coli to antibiotics varied and multiple resistance was 2-8 antibiotics. Presence of THMs and MARBs in well-water is an indication of sewage contamination. A frequent analysis and stringent regulations must be implemented to avoid further environmental deterioration. Agencies need to begin implementing strict regulations to help in the prevention of the spread of pollution and disease.

Keywords

well-water, sewage effluents, Oman, chemical pollutants, antibiotic resistance