Evaluation of the Tigris River's Water Quality in the Wasit Governorate, Iraq

 Corresponding author: Shayma Abdulwahab Luibi Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Evaluation of the Tigris River's Water Quality in the Wasit Governorate, Iraq Shayma Abdulwahab Luibi * Third Rusafa Education, Ministry of Education, Baghdad, Iraq. GSC Advanced Research and Reviews, 2025, 25(02), 025-032 Publication history: Received on 26 September 2025; revised on 02 November 2025; accepted on 04 November 2025 Article DOI: https://doi.org/10.30574/gscarr.2025.25.2.0333 Abstract The objective of this study is to evaluate the water quality of the Tigris River physicochemical and biological properties throughout dry and wet seasons in the governorate at Wasit, Iraq. Five points were selected over the course of the governorate’s river path, and samples of water were measured in both the dry season in September 2023 as well as the wet season in February 2024. The key points that were measured included the pH, EC, TDS, Turbidity, DO, BOD5, and concentrations of heavy metals and major ions, (Fe, Pb, Cd) and (Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl⁻, and SO₄²⁻), respectively. The results were compared with the drinking and aquatic life standards of the World Health Organization, as well as Iraq. To provide an overview of the general state of the water, the WQI of the water was calculated. The results show significant seasonal variation, as well as an overall degradation of the water quality during the dry season. With reduced river flow and higher levels of the untreated home and industrial waste discharge, as well as the runoff from the agricultural areas, most of the parameters, especially TDS, BOD5 and the heavy metals have crossed the permissible limits at many locations. The WQI of the river water lies between “Very Poor” to “Unsuitable” drinking for the humans. This study underlines the immediate necessity of efficient pollution abatement and watershed management strategies in the area. Keywords: Tigris River; Wasit; Heavy Metals; Physicochemical Parameters; Pollution; Water Quality Index (Wqi) 1 Introduction Tigris River in Iraq is an essential freshwater resource that supports industrial activity, agriculture, and millions of people’s access to drinking water. There are several reasons why the river has become increasingly environmentally stressed in the recent past: diminished water flow due to upstream dams in Iran and Turkey and more extended droughts due to climate change, as well as severe pollution from industrial, agricultural, and urban sources. [1-3]. One of the most significant sources of drinking and municipal water supply in the Wasit Governorate, southeast Iraq, is the Tigris River. For this reason, the quality of water in this part of the river matter not only to the health and well-being of the residents of the chosen region but also to the long-term existence of the agricultural sector. The outcomes of the study at hand are particularly useful for determining the status of the specified river concerning the season in question, as well as the locations analyzed. The wide range of water quality measures was analyzed, revealing a concerning picture. The Impact of Employee Diversity Network and Opportunities for a Multicultural Environment [4-6]. Aims The aims of paper are •Identify the seasonal and regional fluctuations in the Tigris River's biological and physicochemical characteristics in Wasit. GSC Advanced Research and Reviews, 2025, 25(02), 025-032 26 • Evaluate the parameters and compare them to international and national water quality requirements. • Calculate the Water Quality Index (WQI) to get a comprehensive evaluation of the potability of the water. • Identifies possible sources of pollution and suggests ways to mitigate them. 2 Materials and Procedures 2.1 Study Region and Sites for Sampling In the Wasit Governorate, five sample locations were chosen along the Tigris River: • S1: Upstream (close to Al-Aziziyah): Indicates the quality of the entering water. • S2: Evaluates the urban effect within Al-Kut City (upstream of the city center). • S3: Impacts of Urban Wastewater Discharge Reflected in Al-Kut City (below the city center). • S4: Agriculturally Used Region (south of Al-Kut). • S5: Near Maysan Governorate borderline. 2.2 Collection and Analysis of Samples The samples of water were collected in September 2023 in the dry season and in February 2024 in the wet one. In ice freezers, the prepared polyethylene bottles previously cleaned were used to transport the samples to the laboratory. All analyses were conducted according to the generally accepted methodologies. 2.3 Analysis of Parameters The anthropogenic and natural marine pollution elements can be classified into physical, chemicals, and ions. Some of the physical ions include turbidity and total dissolved solids TDS, electrical conductivity EC, pH, and temperature. Chemicals are the BOD 5, DO, and phosphates PO4-3 and nitrates NO-3, Primary ions include the sodium Na +, potassium K +, calcium Ca +2 magnesium Mg+2, chloride Cl –, sulfate SO4-2, Finally, heavy metals include cadmium Cd, lead Pb, and iron, Fe. 2.4 Water Quality Index (WQI) Calculation A weighted arithmetic index approach was used to construct the WQI, taking into account important factors (pH, TDS, DO, BOD5, NO₃⁻, and Cl⁻). 3 Results and Discussion 3.1 Parameters of Physicochemistry 3.1.1 pH Showed a modest rise downstream, most likely as a result of algae photosynthetic activity, but remained within acceptable bounds at all sites as shown in Table 1 and Figure 1 [7,8]. 3.1.2 EC and TDS An increasing trend from S1 to S5 during the dry season. The value was above 1000 mg/L for drinking water. The causes were due to evaporation, lesser dilutions, and the intrusion of saline agricultural drainage water into the river. However, due to dilution from rainfall, the wet season had the least concentrations as shown in Table 1 and Figure 2,3 [9, 10]. 3.1.3 Turbidity For both seasons, turbidity was high 1. The causes were different due to the above conditions. During the rainy season, it was due to the surface runoff of transport of suspended particles. However, during the dry season, it implies the proliferation of algae and possibly the discharge of untreated wastewater as shown in Table 1 and Figure 4 [11, 12]. 3.1.4 DO and BOD5 The significant decrease of DO concentrations at the sites S3, S4 and S5, below the 5 mg/L, required for supporting of aquatic life, is an important result. An associated sharp increase in BOD5, an important indicator of organic pollution of GSC Advanced Research and Reviews, 2025, 25(02), 025-032 27 sewage and agriculture sources, is the direct cause of it; it is of extremely serious concern for the ecological health of the river during a dry season as shown in Table 1 and Figure 5,6 [13,14]. Table 1 Seasonal Differences in Physicochemical Characteristics at Various Locations Parameter Standard (WHO/Iraqi) Season S1 S2 S3 S4 S5 pH 6.5 - 8.5 Dry 7.8 7.9 8.1 8.2 8.3 Wet 7.5 7.6 7.7 7.8 7.8 EC (µS/cm) 1500 Dry 1850 2100 2350 2800 2950 Wet 1200 1350 1550 1850 2000 TDS (mg/L) 1000 Dry 1180 1340 1500 1790 1880 Wet 768 864 992 1184 1280 Turbidity (NTU) 5 Dry 8.5 12.1 18.5 22.4 20.1 Wet 25.4 34.2 45.8 55.1 48.3 DO (mg/L) > 5 Dry 6.8 5.9 4.2 3.8 4.1 Wet 7.5 6.8 5.9 5.2 5.5 BOD₅ (mg/L) < 4 Dry 3.5 4.8 7.2 8.5 7.8 Wet 2.1 3.2 4.5 5.9 5.1 Figure 1 PH variation across sites GSC Advanced Research and Reviews, 2025, 25(02), 025-032 28 Figure 2 EC variation across sites Figure 3 TDS variation across sites GSC Advanced Research and Reviews, 2025, 25(02), 025-032 29 Figure 4 Turbidity variation across sites Figure 5 DO variation across sites GSC Advanced Research and Reviews, 2025, 25(02), 025-032 30 Figure 6 BOD variation across sites 3.2 Concentration of Heavy Metals Table 2 displays the concentrations of a few chosen heavy metals. Table 2 Concentration of Heavy Metals (mg/L) Heavy Metal Standard (WHO) Season S1 S2 S3 S4 S5 Iron (Fe) 0.3 Dry 0.25 0.31 0.45 0.52 0.48 Wet 0.18 0.22 0.28 0.35 0.32 Lead (Pb) 0.01 Dry 0.005 0.008 0.015 0.018 0.017 Wet 0.003 0.005 0.009 0.012 0.011 Cadmium (Cd) 0.003 Dry 0.001 0.002 0.004 0.005 0.005 Wet < 0.001 0.001 0.002 0.003 0.003 Fe, Pb, and Cd levels at the agricultural and urban sites increase significantly S3-S5. The levels of Pb and Cd at S3, S4, and S5 above WHO limits during the dry season but Fe slightly exceeds the limit. The sources of these metals include use of phosphate fertilizers and pesticides in agriculture, urban runoff, and industrial discharges. Both cadmium and lead are toxic elements and have the capability to bio accumulate in the food chain posing a severe risk to human health as shown in below Figures 7, 8 and 9 [10-14]. Figure 7 Fe Concentration variation across sites GSC Advanced Research and Reviews, 2025, 25(02), 025-032 31 Figure 8 Pb Concentration variation across sites Figure 9 Cd Concentration variation across sites 3.3 Water Quality Index (WQI) Table 3 provides a summary of the determined WQI values for the dry season. Table 3 Classification (Dry Season) and Water Quality Index (WQI) Sampling Site WQI Value Status S1: Upstream 68.2 Medium S2: Urban (Upstream) 78.5 Poor S3: Urban (Downstream) 115.3 Unsuitable S4: Agricultural 134.7 Unsuitable S5: Downstream 126.9 Unsuitable 3.4 Classification by WQI The WQI provides a complete, clear assessment about the drinkability. The upstream site has a water quality of “Medium”, while the downstream sites have an “Unsuitable” water quality. This spatial degradation clearly identifies the agricultural zones and the parts in Al-Kut city as major hotspots in pollution. The higher level of TDS, BOD5, and nitrates are the main cause of the high WQI. GSC Advanced Research and Reviews, 2025, 25(02), 025-032 32 4 Conclusion This study unequivocally shows that the Wasit Governorate's Tigris River water quality is severely stressed. The primary findings are • Spatial Degradation: As the river flows through Al-Kut city and agricultural regions, the quality of the water drastically declines. • Seasonal Variation: Because there are less flow and concentration of contaminants during the dry season, the water quality is lower. • Major Issues: The main issues include heavy metal contamination (Pb, Cd), salinity (high TDS), and high organic pollution (low DO, high BOD5). • Overall Status: The river water is rated as "Poor" to "Unsuitable" for drinking by the WQI, particularly in locations downstream. Compliance with ethical standards Disclosure of conflict of interest No conflict-of-interest to be disclosed. References [1] World Health Organization (WHO). (2017). Guidelines for Drinking-water Quality (4th ed.). [2] Al-Ansari, N. (2013). 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