Water Quality Status of Tigris River Using Index Analysis

Abstract

This study investigates the effects of Al-Doura oil refinery effluent, in Baghdad city, on the water quality of the Tigris River using the Canadian Water Quality Index (CCME WQI) and Rivers Maintaining System (1967). Water samples were collected monthly from Tigris River at three stations, which are Al-Muthanna Bridge (upstream), Al-Doura Refinery (point source), and Al-Zafaraniya city (downstream) from October 2020 to April 2021. Fourteen water quality parameters were studied, namely pH (6.50-8.10), Water Temperature (WT) (5.00-27.00 °C), Electrical Conductivity (EC) (877.00-1192.00 μs/cm), Dissolved Oxygen (DO) (5.03-7.57 mg/L), Biological Oxygen demand (BOD) (0.53-2.23 mg/L), Total Dissolved Solids (TDS) (455.67-770.00 mg/L), Chloride (Cl) (22.66-84.97mg/L), Sulfate (SO4) (150.00-241.67 mg/L), phosphate (PO4) (0.37-0.57mg/L), Turbidity (Turb) (12.13- 86.13), Total Hardness (TH) (86.19-526.67 mg/L), Calcium (Ca) (60.53-137.61 mg/l), Magnesium (Mg) (46.62-110.45 mg/L), and Alkalinity (Alk) (86.33-171.67 mg/L). The water quality of the Tigris River ranged from 51 to 63, which indicated the marginal status of the river quality. The deterioration of water quality has appeared at Al-Dura Refinery and Al-Zafaraniya city stations, which could be attributed to the industrial activities in these regions. Generally, the results indicated that the Tigris River requires extensive treatment before it can be accepted for domestic.