Unveiling microplastic and metal pollution in giant armadillos (Priodontes maximus) from areas impacted by human activities in the Rio Doce Basin, Brazil

The giant armadillo (Priodontes maximus) is the largest armadillo species, inhabiting vast areas of South America, including forests, savannas, and grasslands. The Rio Doce State Park (RDSP) is an important conservation unit that harbors P. maximus individuals. The largest environmental disaster in Brazil occurred in 2015 when a dam collapse released tons of iron ore tailings into the Rio Doce basin. In addition to this tragedy, plastic pollution is a growing concern for the conservation of this area and raises an alert for microplastic pollution. In the present study, we investigated the presence of microplastics and heavy metals (Al, Cd, Fe, Pb, Cr, Cu, Ni, Mn, Ti, and Zn) in the feces of the giant armadillo from Rio Doce State Park to understand the invisible threats to which this species is susceptible in two areas (North and South) of RDSP. All feces samples were positive for the tested heavy metals and microplastics. Cr, Mn, and Pb levels were significantly higher in the North area, while microplastics were more abundant in the South area. The most common microplastic types identified were polypropylene (PP, 32.5 %), polyethylene terephthalate (PET, 22.5 %), and polyethylene (PE, 15.0 %). Several studies have reported the harmful effects of heavy metals and microplastics on mammals. The simultaneous presence of both contaminants highlights significant concerns for conserving this species and underscores the need for greater attention to the human impacts on RDSP's biota. This study represents an initial approach seeking to understand the exposure levels of a threatened mammal species to two relevant pollutants allowing it to offer support for new strategies for mammal conservation.