Potential adverse effects of heavy metals on clinical health parameters of Caretta caretta from a nesting area affected by mining tailings in Brazil

•A dam collapsed in southeast Brazil affecting a nesting sea turtle area (Povoação).•Many correlations between heavy metals and health parameters were found in Povoação.•Higher As, Cd, Cr, Fe, Pb, and Zn levels in animals’ blood from the affected area.•Sea turtles from Povoação had a worst body condition with higher ectoparasitic and epibiont loads.•They also showed eye lesions and suggestive fibropapillomatosis tumors.