Assessment of the suitability of well water in the Ameriya Al-Fallujah District using the Canadian Water Quality Index (CWQI) for agricultural and human use.

Abstract

Surface water resources in Iraq, particularly in semi-arid regions, are experiencing a rapid decline in quality due to various human pressures. This study aims to conduct an integrated assessment of the water quality of the Fallujah River in the Ameriyah Fallujah district using the Canadian Water Quality Index (CWQI) to determine its suitability for human (drinking) and agricultural use, as well as for the protection of aquatic life. Seasonal water samples (winter, spring, and summer) were collected from ten monitoring stations representing a gradient of human activity along the river. Twenty-seven physical, chemical, and microbiological parameters were analyzed using standard methods. The CWQI was calculated based on the factors of range (F1), frequency (F2), and capacity (F3), using reference standards from the World Health Organization (WHO), the Canadian Council of Ministers of the Environment (CCME), and the Food and Agriculture Organization (FAO). The results showed a clear spatial degradation from the source to the mouth of the river. Water quality was unfit for drinking at all sites (CWQI classification: suspicious to poor) due to systematic exceedances of Escherichia coli and heavy metal (cadmium and lead) standards. Water quality was also suspicious to poor for aquatic life protection at 60% of sites due to excess phosphate, biochemical oxygen demand, and cadmium. For agricultural irrigation, only half of the sites were acceptable, while the other half were classified as suspicious due to salinity risks (high electrical conductivity and sodium uptake). Correlation and principal component analysis revealed strong correlations between organic pollution and urban sources, and between salinity and heavy metals and agricultural/industrial sources. The study concludes that the Fallujah River suffers from severe cumulative pollution, primarily caused by untreated sewage and unsustainable agricultural practices. The research underscores the usefulness of the CWQI as an effective decision-making tool and recommends urgent action to address point pollution sources, establish a sustainable monitoring system, and strengthen institutional cooperation to achieve integrated water resources management.