Nitrates in Turkish waters: Sources, mechanisms, impacts, and mitigation

Abstract Intensive technological developments, rapid population growth, unplanned urbanization, and excessive use of nitrogen fertilizers have caused water resources to be contaminated substantially by nitrates in Turkey as well as across the world as evidenced by the accumulated scientific information. The information should be evaluated to draw a nationwide attention to the problem. The aim of this review article was to highlight the importance of nitrate (NO3) contamination and to discuss the measures to be taken to mitigate nitrate contamination across the nation. Significant number of the peer-reviewed scientific articles were examined to identify anthropogenic sources, spatial and temporal variability, and contamination mechanisms of the nitrate contamination of the water resources across Turkey. Agriculture, especially chemical fertilizers used in irrigated agriculture, was the most important source of nitrates in groundwater. Also, the industrial and domestic discharges from highly populated and industrialized regions were significant sources of nitrates in the water resources. The most severe and widespread nitrate contamination occurred in the regions where intensive agriculture, industrial development, and rapid urbanization coincided. Drinking waters have been exposed to a significant nitrate contamination in many regions across the nation, raising a serious health concern to the people. A well-developed action plan is urgent for mitigating nitrate contamination in Turkish waters to avoid further degradation of those valuable resources.