Lithium in tap and bottled water in Catalonia (NE, Spain): Environmental and health issues

The objective of this study is to compare lithium (Li) concentrations in bottled natural mineral waters and tap water from urban water supplies in Catalonia (NE Spain) and to assess their potential relationships with environmental factors and human health. To achieve this, the chemical composition of 28 bottled mineral water brands marketed in Catalonia has been analyzed, and lithium concentrations in tap water provided by urban supply companies have been compiled.

The highest Li concentrations in bottled mineral waters were observed in the brands Malavella (1250 µg/L), San Narciso (1070 µg/L), and Vichy Catalan (1070 µg/L). These mineral waters originate from Caldes de Malavella (Girona) and are characterized by their thermal origin (58°C), natural carbonation, and high mineralization. Other brands with relatively high lithium concentrations include Aigua de Salenys (619 µg/L) and Aigua de Vilajuïga (570 µg/L). The lithium in these waters is derived from magmatic fractional crystallization and partial melting processes, which concentrate Li in muscovite minerals found in pegmatites and granites. During rock weathering and water-rock interactions, lithium, being highly soluble, is released and transported by water. In contrast, the median Li concentration among the remaining 25 brands of bottled water is 10 µg/L.

In relation to the lithium content of tap water supplied for urban consumption, the company that supplies the Metropolitan Area of Barcelona only controls it. This is because neither European directives nor Spanish regulations currently define a concentration limit for lithium in drinking water. The lithium concentrations of the tap water in the Barcelona Metropolitan Area range between <5 mg/L and 15 mg/L. since the main sources of water supply are river and reservoirs of surface waters.

Emerging research by health organizations has linked the natural occurrence of lithium in drinking water to potential health benefits, such as reduced suicide rates and improved mental health outcomes. However, concerns also exist regarding potential adverse effects, such as impacts on thyroid hormone levels and autism prevalence. This study aims to identify whether drinking water represents a significant dietary source of lithium and to contribute to improving epidemiological research on the health effects of Li. Additionally, the preliminary results provide a reference for the natural lithium background levels in aquatic environments. This baseline can help assess the anticipated impacts of anthropogenic lithium from the growing manufacture and recycling of lithium-ion batteries for electric vehicles.