Desalination and Calcium, Fluoride, and Magnesium Composition: Assessing Water Quality Variations Across Water Sources in Israel

Objective: Due to limited freshwater supplies, Israel increasingly depends on desalination to fulfill its drinking water requirements. However, this process reduces mineral levels such as magnesium (Mg2+), calcium (Ca2+), and fluoride (F−), which could pose health concerns. In this study, we analyze the mineral concentrations across various water sources nationwide. Materials and Methods: We analyzed a national database on drinking water quality for levels of Ca2+, Mg2+, and F− from 2014 to 2024. District-level concentrations were calculated and compared with national means and across primary water sources. Water sources were classified as primarily DSW (DSW) or primarily groundwater-based according to their dominant composition. Results: Nationwide median concentrations were 52 mg/L for Ca2+, 12 mg/L for Mg2+, and 0.15 mg/L for F−. Ca2+ and Mg2+ showed marked regional variation, with significantly higher mean levels in the Northern District (Ca2+: 72 mg/L, p < 0.006; Mg2+: 34 mg/L, p < 0.001) and lowest levels in southern regions, particularly the Southern District (Ca2+: 39 mg/L, p < 0.001; Mg2+: 7 mg/L, p < 0.001) compared to the national average. Fluoride concentrations were generally low, with higher levels in northern regions (0.23 mg/L, p < 0.001) and lower levels in Tel Aviv (0.07 mg/L, p < 0.001) and Jerusalem (0.11 mg/L, p < 0.001). By predominant water source, Ca2+ and Mg2+ concentrations were lowest in DSW (Ca2+: 42 mg/L; Mg2+: 9 mg/L) and highest in groundwater supplies (Ca2+: 83 mg/L; Mg2+: 34 mg/L). Concentrations of F− ranged from 0.12 mg/L in predominantly DSW to 0.23 mg/L in areas supplied primarily by groundwater. Conclusions: Ca2+ levels aligned with international reports, while Mg2+ levels, especially in desalination-reliant areas, remained consistently low. F− concentrations stayed below both the recommended maximums and the optimal levels advised by the U.S. Public Health Service. As desalination efforts grow, concerns have been raised about the potential public health risks associated with low-mineral drinking water, particularly cardiovascular disease and bone disorders.