Groundwater salinization in inland basins of arid and semiarid climates: An overview

Salinization of aquifers is a growing global challenge in the aquifers ability to supply drinking and irrigation water, especially in regions with arid or semiarid climates. An analysis of key recent studies was conducted to identify the factors that lead to the severity of the salinity problem in vulnerable areas. The highest salinity values (averaging 2,000 mg/L to 12,000 mg/L) are reported for the Middle East and North Africa (MENA), resulting from the dissolution of carbonates, gypsum and halite. Intensive agriculture artificially raises the water table, favoring evaporation, which together with the infiltration of irrigation returns, significantly increases salinity. Latin American regions report unsustainable groundwater withdrawals and poor management as their main challenge. Overall, groundwater salinity evolves from Na-HCO3 and Ca-HCO3 types to Na-Cl type. Strategies aimed at reducing salinization consistently emphasize increased monitoring and effective water management practices, which vary according to each region. Two regions, northern Mexico and the food basket of Ghana, illustrate the differences and similarities of groundwater salinization in irrigated semiarid areas.