What’s behind the alarming rise in birth defects in Brazil’s illegal gold mining capital?
In Pará state children are being born with neurological disorders. Experts note similarities to the mercury poisoning disaster in Minamata, Japan – but say that is not the whole story
Seven-year-old Valdenisa squealed with delight as she grasped the tape measure above her head. It was part of a game so that a doctor could measure the circumference of her head and check her withered legs.
She was one of a dozen Indigenous Munduruku children being examined by a trio of child neurologists and geneticists earlier this month in Itaituba, in Brazil’s Pará state. Located on the Tapajós River, the town is known as the country’s illegal gold capital, as it accounts for three-quarters of all the illicit gold produced in Brazil.
Amid a surge in cases of children suffering from crippling physical and neurological symptoms, medics and Indigenous health specialists are asking if contamination caused by illegal gold mining is to blame and have drawn comparisons with the stark black-and-white images of Minamata – the Japanese town at the centre of the worst ever case of mercury poisoning, in the 1950s and 1960s.
Miners use mercury, mostly contraband, as it is banned in Brazil, to extract gold.
More than six out of 10 of Munduruku in three villages were found to have mercury levels above internationally recognised safe norms, and 15% of children had neurodevelopment problems, according to a groundbreaking study by universities, state institutions and civil society in 2020.
The report’s lead author, Paulo Basta, an investigator for Brazil’s National School of Public Health (ENSP), part of the Oswaldo Cruz Foundation (Fiocruz), noticed the “increasingly frequent birth of children with physical abnormalities, intellectual disability and rare neurological syndromes”, over the past decade.
Basta is conducting a long-term study that aims to measure the effects of prenatal exposure to mercury on the neurodevelopment of Indigenous children living in areas affected by gold mining.
“Our goal is to enrol 300 pregnant women and 300 newborns and to monitor the babies until they are two years old,” he says. So far, 91 pregnant women are participating in the study, and 48 children have been born. The study began in March 2023 and will run until December 2026.
Cleidiane Carvalho, a field nurse posted to one of the Munduruku communities in 2010, sounded the alarm when one of her patients in a mining-affected area gave birth to a disabled daughter.
“As soon as I saw the child, I realised she had all the characteristics of a child from Minamata,” she says by phone from Boa Vista, where she worked with the Yanomami, another Amazon people brutally affected by garimpo – as artisanal gold mining is known in Brazil. “I had read about Minamata and made the connections.”
The mother says she was born in a community that has mining activities. “Everything suggests that it was caused by [mercury] contamination. I became even more worried when the patient’s second daughter was born with the same disfigurement,” says Carvalho.
Years later, Carvalho was promoted to regional coordinator of Indigenous health based in Itaituba, where she managed 28 health clinics and 400 employees in six municipalities. In 2017, she was shocked by the demand for wheelchairs in Munduruku villages, which was high and increasing every year.
Alexo, 10, cannot walk. He clings on to his mother, wrapping his legs around her as they sit in the examination room with the medical experts. His father, Aldo Karo Munduruku, short with the wiry build of a man who works with his hands, gently lifts his son on to his feet. He takes a few tottering steps before needing to grasp the back of the bench.
Alexo has microcephaly, an abnormally small head, and he can’t walk or talk due to delayed physical and neurological development.
“I had this beautiful child, but I felt sad because he was a bit deficient,” says Karo Munduruku. “He was never normal, you see. He didn’t play like other children.”
After taking him for MRI scans and physical therapy in Santarém, a day’s journey from Sawré Muybu, the Indigenous territory where the family lives, they decided to use traditional medicine and noticed a slight improvement, he says.
“We used the treatment from our culture, which has traditional remedies like bark, roots and leaves,” Karo Munduruku says. “He started to sit up slowly, to have motor coordination, to move his hand, to talk to himself.”
As scientists try to unravel the mystery around the disproportionate number of disabled children, they have observed that all of the youngsters tested had unsafe levels of mercury in hair samples.
However, poisoning does not explain everything. Claudio Gusmão, coordinator of the paediatric movement disorders programme at the University of São Paulo and one of the visiting experts in Itaituba, says the Munduruku are in a complex chain of circumstances involving mercury poisoning, poverty, poor healthcare and, possibly, a genetic disease.
Gusmão says the team has found some “clearcut cases where there seems to be a genetic disorder”. Mercury intoxication, he says, can explain “a gamut of neurological problems”, but poisoning would not necessarily be what caused them.
Fernando Kok, a child neurologist from the University of São Paulo and one of the group, says there is “no evidence that mercury contamination can damage DNA”.
One theory suggests this might be a genetic disorder more commonly seen in isolated populations. Ganesh Mochida, the principal investigator at the division of genetics and genomics at Boston children’s hospital in the US, says the group had detected an “autosomal recessive condition” in three children with microcephaly.
As the health crisis rolls on, it has become the subject of a documentary called The New Minamata. During the medical examinations, the children’s parents said they ate river fish every day, a source of methylmercury, the organic variety of the toxic metal that passes up the food chain.
The 2020 study shows that estimated daily intakes of mercury from the fish were two to nine times higher than the limits permitted by the UN’s Food and Agriculture Organization.
“In other [Indigenous] territories, there aren’t so many children affected by malformations of neurological illnesses,” says Lucas Albertoni, technical advisor at the special secretariat for Indigenous health at Brazil’s health ministry, adding that an estimated 60 children were affected in a population of about 20,000.
Although there is no existing protocol for mercury contamination, the ministry has worked on a public health framework for Indigenous peoples to confront chronic poisoning in garimpo areas such as western Pará state, Albertoni says.
President Luiz Inácio Lula da Silva, who took office last year, promised to confront the environmental criminals that activists alleged were emboldened by his far-right predecessor, Jair Bolsonaro. Garimpo rapidly expanded during Bolsonaro’s government as he weakened regulations and encouraged the garimpeiros to venture into prohibited areas such as Indigenous reserves and national parks.
Lula’s campaign against illegal mining has had notable success: there was an 84% drop in gold production at mines in the Brazilian Amazon between January and July 2024 compared with the same period in 2022, according to a report by thinktank Instituto Escolhas.
Pará was listed in the study as the place with the most significant drop in gold extraction. But while business has slowed in Itaituba’s gold shops, the culture of gold mining, which dates back five decades, stubbornly holds on.
Cover photo: Children await the arrival of other villagers by the banks of the Cururu river, a major tributary of the Tapajós, for the general assembly of Munduruku people at Waro Apompu village, in Pará state. More than 700 Indigenous people from 102 villages attended. Photograph: Fábio Nascimento/Greenpeace
