Pregnant women in the Munduruku indigenous territory, in Pará state, North Brazil, have mercury levels in their bodies 4.5 times higher than the safe limit established by the World Health Organization (WHO). The maximum safe level is two micrograms of the metal per gram of hair (µg/g), but the levels found in these women average 9.1 µg/g.

The data are part of preliminary findings in a study conducted by the Oswaldo Cruz Foundation and were presented Wednesday (Jun. 3) by the research coordinator, Paulo Basta, during Rio Nature & Climate Week, the climate week in Rio de Janeiro.

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Of the 195 women surveyed, 97 percent have mercury levels in their bodies above the safe threshold. In the most extreme case, one woman had 39.9 µg/g of the metal – 20 times the tolerable limit.

Of this total, 134 women have given birth, and their babies are also being monitored. About 90 percent of them are already born with mercury contamination, as the metal passes from mother to child through the placenta. The babies have average concentrations of 5.8 µg/g, three times the limit. In one extreme case, one of them had 30.8 µg/g, 15 times the safe level.

“This baby is monitored at various intervals throughout the first two years of life. We track growth curves, weight-for-age ratios, height, and other metrics. Our hypothesis is that prenatal exposure to mercury causes delays in these neurodevelopmental milestones,” Paulo Basta said.

“Mercury converts into a neurotoxin that primarily affects the tissue of the central nervous system. Damage to the central nervous system is irreversible. People will have to deal with this problem for the rest of their lives,” he added.

The researcher cites an increase in the number of children born with rare neurological disorders, syndromes, congenital anomalies, and conditions for which a definitive diagnosis has not yet been established. All of these are suspected of being linked to mercury contamination. He also noted that the district where the Munduruku indigenous territory is located was the one that requested the most wheelchairs from the Ministry of Health.

“These data must be turned into official statistics, which did not exist in Brazil until very recently. Our system does not yet have a reporting form for specific cases of mercury contamination,” he stated.

“Despite these limitations, we have 751 identified cases of indigenous people contaminated by mercury with laboratory confirmation. Of this total, 318 are from Pará and 378 are from Roraima, home to the Yanomami people,” he added.

Illegal mining

The region where the Munduruku people live has been affected by illegal gold mining for decades, and mercury is used to separate the gold from the soil. This contaminates the rivers and the life forms in them, and the metal enters the human body primarily through the consumption of contaminated fish.

“Our main source of food is fish, and there’s no escaping that. For those who live in the city, it’s easy. They go to the grocery store, buy chicken and meat – they have other options. It breaks my heart to see the plight of these people, because they have no way to leave their territory and go somewhere else,” indigenous leader Alessandra Korap Munduruku said.

“This is our land. Why do we have to give up our land to companies, gold mining, mining, hydroelectric dams, and railroads? Why is indigenous people’s meat cheaper? It’s as if we didn’t exist. What kind of progress is this that kills rivers, forests, and drives people out?” she asked.