Nitrate Pollution From a Cement Factory and Agricultural Activity: Environmental Impact and Temporal Evolution

Nitrates, common nitrogen-based pollutants, are naturally present in the environment, but their concentrations have risen due to human activities such as agriculture and industry. This study investigates nitrate levels in water, soil, and vegetation within an ecosystem influenced by agricultural fertilizers and emissions from a cement plant located 12 km from Constantine and 7 km from Hamma Bouziane, Algeria. This study, conducted from 2013 to 2023, evaluates the evolution of nitrate pollution from industrial and agricultural sources. Nitrate levels were measured using a selective nitrate ion electrode (Reference CI-6735–NO₃⁻). Samples were collected from drinking water, soils surrounding the cement plant, and crops grown in the region. The results indicate a significant reduction in nitrate pollution despite increased production at the cement plant. Nitrite concentrations decreased by 46%, nitrate levels dropped by 24% in surface and groundwater, and by 60% in industrial fallout dust. Reductions of 65.92% were observed in uncultivated soils, 62%–64% in cultivated soils, and 70% in cultivated vegetation. However, the excessive presence of nitrates in water, especially in the wells of AIN S'DARI (El Hamma region), remains a health risk, particularly due to the potential for methemoglobinemia in infants. It was found that nitrogen-based fertilizers are the main cause of nitrate contamination under the greenhouses, while the cement factory's fallout is the primary pollution source for the surrounding lands. These findings underscore the importance of continued nitrate monitoring and the implementation of strategies to minimize their presence in the ecosystem.