Study of the Water Pollution in the Euphrates River near the Wastewater Treatment Station in the City of Nasiriyah, Iraq

Water pollution is considered one of the most significant challenges and problems facing humanity today. This is due to the transfer of pollutants in water to soil and field crops, particularly heavy metals, due to its cumulative effect and persistance. After the wastewater treatment plant in Nasiriyah was destroyed in 2023, these fields became irrigated with non-treated water. The aim of this research was to study the extent of pollution of the Euphrates River by sewage containing heavy metals such as chromium (Cr), lead (Pb), cadmium (Cd), and nickel (Ni) as well as the chemical and microbial contaminations. Water samples were collected from 10 sites along the Euphrates River, starting from the treatment plant in northern Nasiriyah to the southern end of Nasiriyah City, during both the summer and winter seasons of 2023. Heavy metals analysis results showed that Cr concentrations ranged between 0.02- 0.07ppm in summer and 0.02- 0.08ppm in winter. Pb concentrations fluctuated between 0.2-0.6ppm in summer and 0.05- 0.13ppm in winter. Cd concentrations ranged between 0.01-0.06 ppm in summer and 0.09- 0.10ppm in winter. Ni concentrations varied between 0.03- 0.02ppm in summer and 0.02- 0.03ppm in winter. Concentrations of all the studied elements were within the permissible limits stated by the WHO, FAO with the exception of Cd. The data of chemical analyses showed that the chemical oxygen demand values ​​in winter ranged between 19 and121mg/ L, while in summer they fluctuated between 101 and 941mg/ L. For the biochemical oxygen demand values, ranges between 111and176mg/ L were deteted in the summer and  between 7 and 25mg/ L in the winter, and these values outperformed the permissible limits of the WHO. The E. Coli population outstipped the allowed ranges during the summer (2500–300,000 Bacillus) and winter (8500–39000 Bacillus).