Assessment of Contamination along the Tigris River from Tharthar-Tigris Canal to Azizziyah, Middle of Iraq

Abstract

The Tigris River is the second-longest river in Western Asia and runs through heavily populated areas, especially in Baghdad city with nearly 8 million inhabitants. The water demand is at its highest levels, nevertheless the Tigris discharge has severely declined in the last decades; combined with the fact that the wastewater quantities are increasing, and the wastewater treatment plants are experiencing a deficiency. Four sites were chosen: the Tharthar-Tigris Canal which is located in the north part of Baghdad city, Baghdad city, the Diyala River conjunction with the Tigris River site, and Al-Azizziyah site in the south of Baghdad city near Kut government, to determine the effect of the decreasing Tigris River flow on the water quality and to identify the sources of pollution. In this research, the used method evaluates the concentration of the contaminants along the course of the Tigris River to determine the source of the contaminants as the novelty of this research. The data include the discharge of The Tigris River, a hydrochemical analysis, such as major ions and trace elements, and biological parameters (BOD5, COD, E. coli bacteria, and coliform bacteria MPN/100 mL) as contamination indicators. Multivariate statistical techniques (factor analysis) were applied to evaluate spatial variations, for the years 2005 to 2020, and Phreeqc software was used to assess the saturation indices determine the dominant geochemical processes source responsible for surface water quality. The dominant minerals of the Tigris River were gypsum, anhydrite, and halite. The Tigris River is within the permissible limits for drinking, except at the Tharthar-Tigris Canal and Diyala River, and the main water quality deterioration factors of the Tigris River were recognized as: total dissolved solids, E. coli bacteria, fecal coliform bacteria, BOD5, and COD. By applying the SPSS program, two factors were identified. The first anthropogenic factor discharged into the river represents 71.27% of the variance and is comprised of agricultural land wastewater and sewage water. While the second factor represents 17.02%, indicated by the variables Ca2+, K+, Mg2+, and SO42−. This factor accounts for the chemical weathering of rocky components. It is recommended that a periodic monitoring system is needed to. follow up on pollution levels and water quality for the Tigris River, by conducting seasonal surveys.

Heavy metals pollution profiles in Tigris River within Baghdad city

“…Only PI for Zn has no effect on all sites and for both seasons. While most of the elements have PI values of less than 1, except for Pb, where values are larger than 1 in all sites in both seasons and always fall under the "Seriously Affected" class, which may be due to anthropogenic metals loaded from industrial activity, where the studied area is characterized by the presence of industrial complex plants [20]. In a study by Parissa et al, 2012 [21], it was reported that one of the well-known sources of Pb in water is the deposition of this element from the atmospheric layer to water from vehicular traffic.…”

Using the Organ Model (Owqi) to Evaluate Al-Dandan Water Supply Station and Its Residential Quarters, Mosul, Iraq.

“…In general, all the studied symptoms, despite the presence of a relative height for most of them, were within the permissible limits for drinking, with the appearance of some fecal coliform bacteria cells in some periods. It is noted from Table (4) that the temperatures rise in some periods to reach (20) ˚C, which stimulates the activity of bacteria when present in the water (Oleiwi and Al-Dabbas, 2022).…”

The Influence of the Tigris River Discharge on the Hydrochemistry with Time, from Baghdad to Amara, Southern Iraq

“…The source of these trace elements may be from anthropogenic inputs into soils from different sources, such as agricultural fertilizers, atmospheric deposition, traffic emission, and sewage sludge (Oleiwi and Al-Dabbas ,2022). In general, it is believed that the analyzed trace elements are controlled by parent or source rocks, climatic conditions, pyogenic processes, and drainage where the soils and surface sediments of Mesopotamia terrains are immature with little modifications or alterations by pyogenesis and have undergone degradation by fluvial processes.…”

“…Salinization of the upper part of the Mesopotamia sediments is induced by poor drainage, little rainfall, and very high evaporation rates. The Major ions and trace elements concentration in the surface water appear to have been mainly influenced by the type of source rocks of the Tigris River and its tributaries (Oleiwi and Al-Dabbas ,2022).…”