Lithium in drinking water: Review of chemistry, analytical methods, and treatment technologies

Lithium was included in the fifth Unregulated Contaminants Monitoring Rule, signaling the Environmental Protection Agency's interest in regulating lithium. Many questions regarding occurrence, health effects, and treatability of lithium exist. This review primarily focuses on the relationship between lithium chemistry and treatability. Sampling indicates nationwide lithium occurrence in drinking water. Yet, lithium is not included in the Integrated Risk Information System, reflecting a lack of censuses regarding its health effects. Aqueous lithium is a monovalent cation with size, charge density, and solubility properties that present treatment challenges. Lithium's growing economic value is stimulating new extraction and isolation technologies, but these may not be transferable to drinking water treatment. Currently, reverse osmosis is the only full‐scale drinking water treatment technology that can reliably remove significant levels (>50%) of lithium. Focusing future research efforts on electrodialysis and inorganic ion sieves may yield significant gains in effectiveness and readiness for the drinking water industry.