Toxic Elements in Liometopum apiculatum (Formicidae: Dolichoderinae) from an Abandoned Mercury Mining Site

This study was conducted in the abandoned mercury mining zone in San Luis Potosí, Mexico, where arsenic and mercury contamination poses an environmental issue. This zone overlaps with the distribution range of Liometopum apiculatum (Formicidae: Dolichoderinae), an edible ant that serves as an economic resource for the local population. Due to the potential threat from these pollutants, we assessed the species´ exposure to arsenic and mercury at the contaminated mining site (MS) and a reference site (RS). Additionally, a spatial analysis was conducted to identify overlap between the potential distribution of L. apiculatum and mercury mines across San Luis Potosí. Pollutants were measured in soil, anthill soils, middens, leaves (Larrea tridentata), maguey stalks (Agave sp.), scale insects (Hemiptera: Coccoidea), and worker ants. Arsenic and mercury concentrations were significantly higher at MS than RS. Arsenic levels in soil, anthill soil, middens, and ants were 38, 11, 9, and 4 times higher, respectively. Mercury concentrations in soil, anthill soil, middens, leaves, stalks, scale insects, and ants were 488, 239, 538, 13, 105, 8, and 7 times higher, correspondingly. Ant exposure occurs through soils, anthill soils, and middens (arsenic), and through plants and scales insect secretions (mercury). Spatial analysis identified 92 mercury mines in San Luis Potosí, with 73% located in areas of high L. apiculatum distribution probability. These findings highlight the risks for L. apiculatum posed by mercury mining and the need for further assessments in regions with overlapping mercury mining and ant distribution.