Mining companies operating in the Amazon are poisoning dolphins with mercury. Also the more than 140 hydroelectric installations and the planning of an additional 160 is generating dire consequences for the conservation of these cetaceans.
Hydroelectric dams isolate dolphin populations, disconnecting them from the main channels and their food source, which is fish. This creates a significant threat to their reproduction, to which is added the great mortality of eggs and young dolphins in the turbines.
A group of scientists was dedicated to monitoring 29 dolphins that inhabited the river with satellite transmitters. From there the alarming data about his condition emerged.
The species that inhabit the Amazon are the Inia geoffrensis, better known as the pink dolphin, and Inia boliviensis or Bolivian bufeo. This monitoring that the scientists did, between 2017 and 2019, was carried out in six large hydrographic basins throughout Bolivia, Brazil, Colombia and Peru, where these cetaceans move, feed and reproduce.
“Illegal mining and mercury threaten life in the Amazon and around the Orinoco River. One hundred percent of the tagged river dolphins were contaminated with mercury, especially in the Orinoco basin where there is a large illegal mining arc”Near the border between Colombia and Venezuela, specified the report issued by the scientists.
Mercury is a metal used in mining to separate gold from other elements and is highly polluting. However, the WWF-Brazil conservation specialist, Marcelo Oliveira, clarified that its use in mining is not the only problem.
“Mercury exists naturally in the Amazon, but it comes out of its natural form due to fires, deforestation and the aggravation of rivers. Thus it is carried into the water and enters the chain through fish, consumed by dolphins and people. Pollution is caused by the consumption of fishHe explained.
The high presence of mercury obtained in samples taken from dolphins also represents a threat to the health and livelihoods of the 20 million inhabitants of the Amazon region.
On the red list
The pink dolphin, one of the two species studied, is classified "endangered" on the red list of the International Union for Conservation of Nature. "It is the second most serious threat level for an animal and indicates that the species may be extinct in the near future“Explained WWF-Brazil.
The observation of dolphins showed that these animals require various types of aquatic environments and their life areas exceed in extension those of other terrestrial mammals, so the construction of dams in the Amazon region threatens their life cycle because it breaks the connection from rivers and isolates populations.
The researchers also concluded that the dolphin movements do not distinguish international borders, making necessary agreements between countries to guarantee the protection of the species.
In this sense, the participating institutions seek that the results serve to promote coordinated efforts between governments.
In the next phases, the study will focus on determining more sensitive areas in which infrastructure projects should not be built in order to safeguard these species, as well as monitor the impact of dolphin hunting.