The study, carried out in October 2022, found 100 percent of participants were contaminated with the toxic metal, including 84 percent with levels above the limit recommended by the World Health Organization, two micrograms per gram of hair.

Another 10.8 percent had mercury levels above six micrograms per gram of hair, which requires special medical attention.

It found degenerative nerve diseases in about 30 percent of participants—a condition linked to mercury poisoning.

In 2023, President Luiz Inacio Lula da Silva deployed the army and police in a bid to evict an estimated 20,000 illegal miners from Yanomami territory. But activists say the isolated Indigenous group remains extremely vulnerable.