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Mining exposes Indigenous women in Latin America to high mercury levels

  • A study carried out by the International Pollutant Elimination Network (IPEN) and the Biodiversity Research Institute (BRI) analyzed the levels of mercury in the bodies of 163 Indigenous women of childbearing age.
  • The study authors found considerably high levels of mercury in women from two Indigenous groups in Bolivia who base their diet mainly on fish they obtain from rivers near gold mines.
  • According to the researchers, mercury in the mother’s body can put their health and that of their fetuses at risk.
  • Communities evaluated in Brazil and Venezuela also had mercury in their bodies; in Colombia, Indigenous groups without nearby gold mining and with non-fish-based diets had the lowest levels of mercury.

A recent investigation has found dangerously high levels of mercury among women from different Indigenous communities in four Latin American countries. This chemical element is a neurotoxic substance that presents a severe threat to both women’s health and that of fetuses.

The International Pollutant Elimination Network (IPEN) and the Biodiversity Research Institute (BRI) analyzed the levels of mercury present among women in Bolivia, Brazil, Venezuela and Colombia living near areas where gold mining is carried out using mercury.

The researchers took hair samples from 163 women of childbearing age (18 to 44 years) in those countries and analyzed them at the BRI labs in Maine, United States.

They found that 58.8% of them exceeded the threshold established by the United States Environmental Protection Agency (EPA) of 1 part per million (1 ppm), a level at which harmful effects begin to occur in the development of fetuses, and that 68.8% of the women exceeded the level of 0.58 ppm, the lowest concentration in which there are recognizable negative impacts on the fetus.

According to the report, “Mercury Exposure of Women in Four Latin American Gold Mining Countries,” women from the Bolivian communities of Eyiyo Quibo (in the country’s northwest) and Portachuelo (center) had the highest levels of mercury, with an average of 7.58 ppm.

The researchers also found high levels of mercury among communities in Venezuela and Brazil. In the Venezuelan town of El Callao (east), women showed an average mercury level of 1.1 ppm. In the Brazilian town of Vila Nova (northeast), the women analyzed had an average mercury level of 2.98 ppm.

What these communities have in common is a diet based mainly on fish caught in rivers that are in contact with mines where gold is extracted.

In the western Colombian region of Iquira, where, according to the authors, there is mercury-free gold mining and the diet of the communities examined is not based on fish, the lowest levels of this element were found, at only 0.25 ppm.

Yanomami children at a health seminar run by SESAI (Special Secretariat of Indigenous Health) held in the Yanomami Territory. Many Yanomami have high levels of toxic mercury in their blood due to illegal mining operations within their territory. Photo by Secretaria Especial de Saúde Indígena (Sesai) via Flickr (CC BY-NC-SA).

Possible solutions

According to Lee Bell, IPEN’s policy adviser for mercury and other persistent organic pollutants (POPs), it’s crucial to evaluate mercury contamination in Indigenous communities in gold mining regions (along with associated river systems) because they are heavily dependent on food from the rivers and forests, especially fish.

“If their food sources are contaminated, they have no alternative but to eat them, increasing their body burden of mercury. They don’t have easy access to shops or have money to buy other types of food. They also have minimal medical assistance, and this combination makes them very vulnerable compared to other populations,” Bell told Mongabay via email.

Bell noted that the study shows that Indigenous people in Bolivia living far apart (Eyiyo Quibo is 300 kilometers, or 186 miles, from Portachuelo, for instance) on the same river system had high mercury levels from the fish they eat.

“This suggests that many other Indigenous people relying on these river systems may also be affected by mercury and flags the need for government intervention to stop the mercury use, assess the health impacts on Indigenous people and provide medical assistance to those affected,” Bell said. “This is not limited to Bolivia but would affect many gold mining countries in Latin America where Indigenous people rely on fish from rivers in gold mining regions using mercury.

“Indigenous people rely on the land and rivers for their sustenance and survival. If those lands and rivers become contaminated with mercury, the fish will inevitably have elevated mercury and impact people who eat them,” he added. “This study has shown you can live hundreds of kilometers apart on the same river system and have the same high mercury levels from contaminated fish moving throughout these river systems.”

When asked about possible solutions or alternatives for these women, Bell said that while they cannot easily change their source of food, they can reduce their mercury intake by eating different species of fish, for example, eating more omnivorous species (those that eat both plants and other fish).

“Our information shows that carnivorous fish have the highest mercury levels because they accumulate mercury from eating other fish. Omnivorous fish have much lower mercury levels, and fish eating only plants have very low levels. If these women eat mostly omnivorous and plant-eating fish, they can lower the mercury levels in their body,” Bell said.

He added that another way to avoid fish with high mercury is to eat the smaller and younger fish of any species instead of the large, older fish, because mercury accumulates more in the latter. This, Bell said, is particularly important if the women are pregnant or considering having a baby.

Diagram showing EPA advice for fish consumption. Mercury is particularly problematic during developmental stages, so these limits are designed to protect women who might become pregnant and children aged 12 or younger. Image by Bretwood Higman/Ground Truth Trekking via Wikimedia Commons (CC BY 3.0).

“However, this is a serious impact on their traditional ways and reduces their dietary choices even further when their food supply is already precarious. It makes more sense to ban mercury and keep it out of the river systems. But as a short-term measure, it can help these women,” Bell said.

Bell also said that IPEN has been conducting studies on mercury levels in women of childbearing age across the globe for many years. These studies include small island developing states in the Pacific and Latin America, locations in Africa, Asia, Alaska and Eastern Europe, and many more.

“As long as governments allow the use of poisonous mercury in gold mining, IPEN will continue to monitor vulnerable populations and expose the impacts of this toxic trade in mercury,” Bell said. “We are discussing opportunities to conduct further sampling in Latin America and will keep you informed of our progress.”


Bell, L., Evers, D., & Burton, M. (2021). Mercury exposure of women in four Latin American gold mining countries. Retrieved from International Pollutants Elimination Network (IPEN) website:

Banner image: Indigenous women and children at a workshop on food and nutritional surveillance in the Sanomã Community. Image by Secretaria Especial de Saúde Indígena (Sesai) via Flickr (CC BY-NC 2.0).

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