More than 20% of 1,010 fish tested across six Amazon states carried mercury above the safety limit set by Brazil's health authorities, according to the Oswaldo Cruz Foundation, a research institute under the Health Ministry.
At dawn on the Tapajós, a tributary of the Amazon, fresh fish begin arriving at the market in Itaituba. Eateries selling river fish such as tambaqui, piau and matrinxã fill with customers. After dark, stalls appear in the square to grill tambaqui over charcoal. "The fish here is good, isn't it," the owner of one restaurant said.
Itaituba is a gold town. Upstream, mercury is used to extract gold and is released into the water every day.
In 2023, a news anchor for the Brazilian media group Globo said on television: "As a result of illegal mining, the health of residents is under threat."
What the tests found
The foundation tested fish sold at public markets and elsewhere in 17 cities across six Amazon states between 2021 and 2022. The samples covered 80 species.
The survey began with a letter. In 2017, a woman of the Munduruku, an Indigenous people living in the Tapajós basin, wrote to the foundation: "Help! I can hear the forest screaming."
The findings put the risk to mothers and children at the center of the story. Mercury accumulates in fish and passes to people who eat it, and the concern raised by the survey is that routine meals of river fish may carry exposure above what food-safety limits assume.
“These are alarm-level numbers.”a doctor involved in the survey, physician
The series, "Corroded Amazon: Gold Rush, Mercury's Shadow," runs in six parts. The first installment follows a miner's gold through the hands of Indigenous people who carry its "suffering." The second profiles a boy in a wheelchair in a fishing village who asks, "Why can't I walk?"
Brazil's president has condemned the threat to Indigenous peoples in the deep Amazon as "genocide." The series appears in the year Japan marks 70 years since Minamata disease was officially confirmed, a poisoning caused by industrial mercury discharged into the sea.