Effect of Hartha and Najibia power plants on water quality indices of Shatt Al-Arab River, south of Iraq

Abstract

The main object of this research is to assess the water quality of Shatt Al-Arab River and its suitability for various purposes near power plants (Hartha and Najibia) through physical and chemical analysis [temperature, pH, EC, Cl−, Na+, K+, Ca+2, Mg+2, HCO3−, NO3−, SO4−2, Fe+, total alkalinity, total hardness, biological oxygen demand (BOD5), NH4+, and NO2−] using water quality index (WQI), organic pollution index (OPI), sodium adsorption ratio (SAR), and percentage of sodium ion (Na%) during the dry season (August, 2016) and the wet season (January, 2017). WQI of Shatt Al-Arab falls under very poor quality during summer season, while it ranges from very poor quality to unsuitable for drinking purposes during winter season. There is a clear effect of power plants on water quality. Hartha and Najibia power plants contribute to the deterioration of water quality by increasing the percentage ratio of WQI near these plants by 13.22 and 9.69%, respectively, compared to the north sites of these plants during summer season. The percentage ratios of increased WQI near Hartha and Najibia power plants compared to the north sites of these plants are 17.93 and 15.92%, respectively, during winter season. Water quality of Shatt Al-Arab falls under a high level of organic pollution during the summer and winter seasons. There is a slight effect by the power plants on the OPI. Hartha and Najibia power plants contributed to the change of the OPI by 10% compared to the north site of Hartha power plant. According to the comparison between the SAR values which represent the suitability of water for serve irrigation purposes and SAR values of Shatt Al-Arab, all sites lie in the first class (excellent). According to Na+%, the type of surface water in the studied area lies in good class during winter season and permissible class during summer season.