Origin of boron from a complex aquifer in southeast of Spain

A study of the boron content alongside Cl ^-, SO ₄ ^2-, and NO ₃ ^- ions has enabled the factors that determine its origin to be distinguished. In carbonate rocks, with their higher saline content, boron is associated with marine intrusion. In the Plioquaternary aquifer, its origin is complex and is associated with three processes: marine intrusion, where there is a high Cl ^- content and the B/Cl ^- ratio is close to that of seawater; anthropogenic pollution, at points with high B and NO ₃ ^- concentrations and where the B/Cl ^- ratio is higher than that of seawater; and the dissolution of evaporite deposits present in the Plioquaternary strata, at a series of sampling points where the SO ₄ ^2-/Cl ^- ratio is elevated and B content is high.