Evaluation of Euphrates River Water Quality on Phytoplankton Biodiversity in Ramadi, Iraq

Water quality deterioration is a major global issue due to population growth and rapid economic development, making healthy water essential for human societies' and ecosystems' sustainable development. Therefore, the current study aims to evaluate the quality of Euphrates River water through its chemical and physical parameters, as well as the distribution of the phytoplankton community. An environmental comparison was conducted between three stations in Ramadi city to assess the Euphrates River's water quality. The comparison was based on physicochemical and biological variables. Fifteen environmental parameters were measured: temperature, pH, electrical conductivity, dissolved oxygen, biochemical oxygen demand, total turbidity, total dissolved solids, alkalinity, bicarbonate, nitrate, sulfate, phosphate, calcium, magnesium, and chloride. The occurrence of seasonal phytoplankton communities was also examined, and the Palmer diversity index, water quality index, and Pearson correlation were calculated. Significant differences were found in the physical and chemical variables of the Euphrates water between studied stations, and in the biological diversity of phytoplankton. The highest average temperature was 26.5 °C at station 1, the highest average pH was 7.575 at station 3, and the electrical conductivity was high at both stations 1 and 3, reaching 810 µS/cm. The Biochemical Oxygen Demand (BOD) ranged from 1.375 to 1.675 mg/L, the lowest average total hardness was 304.5 mg/L at station 3 and the highest average was 310.75 mg/L at station 1. In addition, the study revealed a high diversity in phytoplankton species and groups. 45 genera of green algae were found at all stations, while only 4 genera of Euglenophyceae and Dinophyceae were found. The study confirmed that the quality of the Euphrates River's water is medium and is characterized by high contamination with organic materials, according to the pollution index for water. It was concluded that phytoplankton groups are a sensitive and useful indicator of waterway health.