Mercury in fish
A study of bocachico and moncholo analyzed 160 fish and reported significantly higher methylmercury concentrations in exposed areas, with Bajo Cauca among the most affected.
Read the National University study ↗
Follow the evidence. Discover the mercury pathway. Protect the Cauca.

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AERIS ORDER · 10 ENGLISHExplore the problem. Follow the evidence. Become a Guardian.
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Start with the river and understand the context before entering the challenge.
The Cauca connects ecosystems, communities, wildlife, agriculture and cities. What happens to the water can matter far beyond one location.

Illegal mining can involve excavation, vegetation loss, increased sediment and, in some contexts, hazardous substances such as mercury.

A 2024 report described a mercury seizure in Caucasia.

A 2024 report described phytoremediation over 30 hectares in Caucasia.

A 2026 report described an operation against illegal mining in Caucasia.

Water connects places: upstream events can matter downstream.
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In the Bajo Cauca region of Antioquia, gold mining has been an important source of mercury pollution. Studies in the Bajo Cauca River have found methylmercury concentrations in fish exposed to mining areas.

In aquatic environments, some mercury can be transformed into methylmercury. This form can build up in fish tissues and increase as it moves from one organism to another through the food web.


Three sources. Three ideas. Check the evidence before the challenge.
Official environmental reporting describes impacts from mining in the Bajo Cauca reaching connected water systems, while scientific research has measured methylmercury in fish from exposed areas.
A study of bocachico and moncholo analyzed 160 fish and reported significantly higher methylmercury concentrations in exposed areas, with Bajo Cauca among the most affected.
Read the National University study ↗MinAmbiente has documented how environmental impacts in Bajo Cauca can extend downstream through connected water systems and affect other regions.
Open the official report ↗In April 2026, the Commission of Guardians validated an action plan focused on ecosystem restoration, fisheries, community participation and sustainable livelihoods across the Cauca basin.
See the 2026 update ↗Open the original scientific and official material behind the mission.
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FIELD PROFILE · EVIDENCE FIRSTAsk questions about the Cauca River, Caucasia, illegal mining, mercury, fish and environmental protection.
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