Critical Heavy Metal Contamination in the Tigris River, Baghdad: A Comprehensive Assessment Using the Metal Index (MI)

One of the most important rivers in Iraq is the Tigris River, which serves as the primary source of drinking water and irrigation for agricultural purposes. In recent events, researchers have identified growing concerns about heavy metal contamination in the river. To decide the status of the Tigris River, the metal index (MI) was used in this study. To conduct this study, three locations were chosen along the river, and eight likely harmful heavy metals were examined: iron (Fe), lead (Pb), nickel (Ni), zinc (Zn), chromium (Cr), cadmium (Cd), manganese (Mn), and copper (Cu). The results were worrying. The metal index (MI) shows a clear sign of water quality, and it surpassed the safety measures of all the monitoring stations. Throughout the same locations, the MI values during the dry season were 5.8, 10.21, and 12.22 at stations S1, S2, and S3, although during the wet season, concerning results appeared with values of 5.78, 7.08, and 12.22. The most notable pollutant that exceeded the allowed limits persistently throughout the study period was lead at S2 and S3 (0.092 mg/L and 0.191 mg/L) during the dry season, and at S3 0.181mg/L during the wet season, followed by a large amount of chromium and iron. This can be seen as one of the reasons for the increase in the concentration of heavy metals in industrial waste released from many factories throughout the river, and the direct flow of untreated sewage into the water. These discoveries shed light on the urgent need for environmental intervention on the Tigris River to help protect human health and aquatic ecosystems.