Monitoring the Water Quality of Tigris River by Applied Overall Index of Pollution

The alteration in the hydrological regime in Iraq and the anthropogenic increasing effect on water quality of a lotic ecosystems needs to continuous monitoring. This work is done to assess the water quality of Tigris River within Baghdad City. Five sites were selected along the river and ten physicochemical parameters and Overall Index of Pollution (OIP) were applied to assess the water quality for the period between November 2020 and May 2021, the studied period were divided into dry and wet seasons. These parameters were water temperature, pH, dissolved oxygen (DO), biological oxygen demand (BOD), total hardness, alkalinity, turbidity, total phosphorus, total nitrogen, electrical conductivity (EC). Results showed that the values of parameter indicated slightly polluted in terms of values of DO, BOD and EC in both wet and dry seasons. The findings of the present study showed the OIP values in wet season less than recoded in dry season at all sites. The OIP values ranged between class 2 and class 3 (Acceptable – Slightly polluted ). While sites 2 and 3 were recorded OIP values less the 2 in wet season. However, the variation in OIP- WQI value in five different areas are attributed to impact of different pollutants.