As and ${\mathrm{F}}^{-}$ cooccurrence in drinking water: critical review of the international scenario, physicochemical behavior, removal technologies, health effects, and future trends

Drinking water contaminated with As and \({\mathrm{F}}^{-}\) is increasingly prevalent worldwide. Their coexistence can have negative effects due to antagonistic or synergistic mechanisms, ranging from cosmetic problems, such as skin lesions and teeth staining, to more severe abnormalities, such as cancer and neurotoxicity. Available technologies for concurrent removal include electrocoagulation ~ adsorption > membranes > chemical coagulation > , and among others, all of which have limitations despite their advantages. Nevertheless, the existence of competing ions such as silicon > phosphate > calcium ~ magnesium > sulfate > and nitrate affects the elimination efficiency. Mexico is one of the countries that is affected by As and \({\mathrm{F}}^{-}\) contamination. Because only 10 of the 32 states have adequate removal technologies, more than 65% of the country is impacted by co-presence problems. Numerous reviews have been published concerning the elimination of As or \({\mathrm{F}}^{-}\). However, only a few studies have focused on the simultaneous removal. This critical review analyzes the new sources of contamination, simultaneous physicochemical behaviors, available technologies for the elimination of both species, and future trends. This highlights the need to implement technologies that work with actual contaminated water instead of aqueous solutions (55% of the works reviewed correspond to aqueous solutions). Similarly, it is necessary to migrate to the creation of pilot, pre-pilot, or prototype scale projects, because 77% of the existing studies correspond to lab-scale research.