| Popis: |
Lithium (Li, atomic number 3), the lightest metal on Earth, is in growing demand due to its use in batteries to power various electrical devices and electric vehicles. Li is also used to stabilize mood and prevent suicide in patients with affective disorders. Geochemical mapping provides a means of visualizing spatial variations in the chemical composition of the surface of the Earth. The objective of the study was to determine the concentration and distribution of Li in soils to identify areas with potential for prospecting and look for relationships with human health. The research was carried out between 2003 and 2017 in 13 Brazilian states, covering an area of 3,313,750 km², in which 3688 soil samples were collected in a grid of 25x25km (625km²). The samples (2kg) collected at the top of the B horizon (up to 30 cm) were reduced at the laboratory with aqua regia and analyzed by ICP-MS. The data indicate that in the total of the 13 states, the concentration of Li in the soils (mg/kg) ranges between 0.5 and 167, with a median of 2. Higher levels stand out in the states of Paraíba (0.5-167.15), Ceará (0.7-63.7), Pernambuco (0.5-63.7), Minas Gerais (0.5-83.2), Alagoas (2.0-40.4) and Mato Grosso do Sul (0.5-61.2). In the Pernambuco and Minas Gerais states, the highest values overlap with the Borborema Province and District of Araçuaí, respectively, which already produce Li hosted in pegmatites and have the potential for new deposits. Anomalous Li values above 11.75 mg/kg (estimated as national reference) cover a prospective area of around 25,225 km², distributed for 140 municipalities, or approximately 0.76% of the studied area. On a regional scale, there was no causal correlation between state suicide rates and the levels of Li in the soil. |
