Nitrate Contamination in Groundwater of Arid and Semi-Arid Regions, Ecotoxicological Impacts, and Management Strategies

Groundwater is the primary source of drinking and irrigation in arid and semi-arid regions. In the last few decades, groundwater contamination by nitrate has reached its maximum levels. Several geogenic and anthropogenic sources were found to be responsible for the nitrate contamination. Studies around the globe show that the extensive use of nitrogen-based fertilizers is the principal cause of nitrate contamination in arid and semi-arid aquifers. Nitrate in the drinking water can harm human health by resulting in methemoglobinemia, infectious diseases, thyroid problems, and increased risk of colorectal cancer. Therefore, the growing demand for groundwater, especially in arid and semi-arid regions, necessitates the development of effective nitrate removal strategies. Several existing technologies, such as reverse osmosis, ultrafiltration, chemical and biological denitrification, ion exchange, adsorption, and electrodialysis, can remove nitrate from groundwater. However, their applicability is contingent on several variables, including necessary infrastructure, the cost-effectiveness of the technology, scalability, and its widespread acceptance. Management of nitrate-contaminated groundwater entails source reduction, removal or transformation technologies, groundwater conservation, education, legislation, and guiding principles. Thus, this chapter focuses on nitrate contamination in groundwater, health and environmental impacts, management strategies, and options for safe water supply in arid and semi-arid regions worldwide.