Assessment of water quality in Kirkuk city: using geographic information systems and multi-linear regression analysis

Climate change, pollution, and the degradation of water quality are making it harder to provide safe drinking water globally. For ensuring water safety, it is important to analyze its chemical and physical properties. Assessing the suitability of tap water for consumption according to World Health Organization (WHO) standards and Iraqi standards using GIS techniques and multi-linear regression analysis in Kirkuk City, Iraq, the study examines fourteen key water parameters across multiple city locations and conducted over 2020 and 2022, including pH, turbidity, conductivity, alkalinity, hardness, various ions, dissolved solids, temperature, and chlorine. GIS mapping was used to visualize the spatial distribution of these parameters, while multi-linear regression analysis was employed to identify statistical relationships between turbidity and other water quality indicators. The pH level of tap water in Kirkuk has been shown to be slightly to moderately alkaline, and turbidity exceeded acceptable limits in some locations and decreased slightly in 2022 from that in 2020. It was observed that total dissolved solids decreased during the period of this study and were under permissible standard limits. Electrical conductivity and total hardness remained stable and acceptable. The concentrations of most of the ions, including calcium, chloride, magnesium, sulfate, sodium, and chlorine, were lower than those of WHO and Iraqi standards. Potassium levels varied, meeting standards in some areas in 2020 but falling below WHO recommendations everywhere by 2022. The regression analysis revealed that turbidity was significantly influenced by total dissolved solids, electrical conductivity, and total hardness, with a strong correlation (R2 = 0.939), indicating that changes in water quality parameters are interdependent. However, the R2 value for single linear regression suggests potential variability, emphasizing the need for further data refinement and additional explanatory variables. The study highlights the need for ongoing monitoring and improvement of Kirkuk's water treatment processes, demonstrating the value of GIS-based spatial analysis combined with statistical modeling for identifying areas with compromised water quality and implementing targeted interventions to address these issues.