"For the communities of the Amazon, a land defined by its rivers, fish has always been an important part of the diet. In the northern reaches of the Amazon, the top four species are tucunaré, pirapucu, trairão and mandubé.
But small-scale gold mining has turned these fish into an often deadly health hazard. According to a study published in July in the International Journal of Environmental Research and Public Health, mercury levels found in pirapucu (Boulengerella cuvieri) were four times higher than the safe limit established by the World Health Organization (WHO).
The researchers analyzed 428 samples of fish caught between 2017 and 2018 in five rivers in the Brazilian state of Amapá. The collection points were close to potential mining areas, where mercury is often used to separate gold from ore. The result: detectable levels of mercury were found in all samples. In 28.7% of them, the amount exceeded the WHO limit."