Study around the Barroso mine (Portugal): Baseline levels of lithium for assessing future exposure and risks from Li mining activity.

ABSTRACT

The energetic green transition is increasing the demand for lithium (Li) exploitation. However, the Li supply faces challenges like limited reserves and environmental concerns. This pioneer study aims to characterize the Li concentrations in the region around the Barroso mine, in Portugal, by collecting and analyzing samples of cabbage, potato, drinking and irrigation water and soil from two nearby sites, and performing a preliminary exposure and risk assessment of local populations. Li levels ranged between 20 and 589 µg/kg in cabbages (n = 23), 2.3-21 µg/kg in potatoes (n = 21), 1.1-5.9 µg/L in drinking water (n = 10), 1.1-15 µg/L in irrigation water (n = 23) and 35-121 mg/kg in soils (n = 23). Significant differences in Li content between sampling sites were observed only for cabbage samples. The risk assessment revealed that none of the participants exceeded the provisional reference dose (p-RfD) (2 µg/kg bw/day), with a hazard quotient (HQ) < 1, suggesting no health concerns for the population. It is expected that the studied area will be affected by the future expansion of the mine concession, thus this pioneer study is crucial for future research as it establishes a initial database for evaluating the potential impact of mining activity on the environment and the population's exposure to Li.