Isolation and Identification of Some Algal Species from the Discharges of Samarra Thermal Power Station in Al-Ishaqi District and Their Relation to Selected Physicochemical Variables

This study assessed the impact of effluents from the Samarra Thermal Power Station on the physicochemical properties of the Tigris River in the Al-Ishaqi district, Salah Al-Din Governorate, Iraq. Algae were also investigated as bioindicators to evaluate water quality and ecological changes caused by industrial discharges. Water samples were collected from four sites along the Tigris River within the Al-Ishaqi area during autumn and winter (November 9, 2024–February 20, 2025). On-site measurements of selected parameters were conducted immediately after collection, while other samples were preserved for laboratory analysis. Additional samples were used for the isolation and identification of algal species. pH values were generally within the Iraqi permissible range (6.5–8.5), except for a minimum value of 5.97. Electrical conductivity reached a maximum of 1075µS/ cm in winter, likely due to runoff and sediment erosion. Total dissolved solids ranged from 221 to 956.25mg/ L, showing spatial and temporal variation indicative of external pollution inputs. Dissolved oxygen decreased in certain locations, suggesting organic waste influence. Chloride levels showed no significant differences, while sulfate concentrations peaked at 240ppm in winter. Alkalinity ranged from 87.93 to 212ppm with clear spatial differences. Algal genera identified included Navicula, Zygnema, and Cladophora, with greater diversity observed in autumn, reflecting seasonal nutrient shifts. Effluents from the Samarra Thermal Power Station significantly influenced several physicochemical parameters of the Tigris River, especially during the winter season. Variations in water quality and algal diversity highlight the combined effects of seasonal changes and surrounding pollution sources.