According to a study published in the journal “Nature Communications”, the forests of the southeastern Peruvian Amazon absorb high levels of mercury, from informal and illegal mining, which are toxic to the region’s biodiversity.
Madre de Dios is the department where the investigations were carried out, one of the most affected by the depredation of the jungle in search of alluvial gold, which in the last decade has only increased by 40% in the protected areas of the country.
“The mercury levels we found were completely unexpected, I couldn’t believe it, they were much higher than anywhere else.“, reports Jacqueline Gerson, American biogeochemist and lead author of the research.
To carry out the study, soil, air and vegetation samples were taken at 3 locations adjacent to the land where the mining activity is taking place and at two locations a little further away. The findings showed that the nearest primary forest areas contained between two and fourteen times more amounts of mercury than other areas further away.
Specifically, in one of the locations, known as the Los Amigos Biological Station, which has an area of 146,000 hectares, the mercury load exceeded concentrations reported in other studies conducted in ecosystems around the world. entire. The results are comparable to the areas affected in China by the industrial combustion of coal.
On the contrary, in the deforested areas of the zone of auric metalliferous activity, a lower load of the metal was detected, which suggests that the forest complexity of the Amazonian biodiversity makes this region very vulnerable to a greater accumulation of mercury.
“The large amount of leaf cover acts as a perfect surface for the mercury (…), since it is precisely the presence of this thick canopy that is important in removing this mercury from the atmosphere and bringing it to the forest.Gerson Highlights.
An infiltrator in nature
The problem arises after the mining activity of extracting gold informally or illegally. Forests are devastated by the felling of trees, the suction of soil with dredges, and the use of mercury to separate the gold and generate an amalgam which is then burned, emitting gaseous mercury into the atmosphere.
Gerson says that these metallic particles are very volatile and, carried by the air, adhere to the leaves of the vegetation. Then, with the rains, they are washed down to the forest floor.
The mercury is not only dragged, but the leaves absorb it through their tissues, infiltrating the entire plant and then contaminating the food web and affecting various birds in the jungle.
“These are levels known to be dangerous. Decreases reproductive success by 30%, may cause developmental issues, neurological effects, alter behavior and songs», Develops Gerson.
The researcher suggests that a possible way out is the formalization of mining activity in the region, although it is known that the damage caused by the mercury already used will last for centuries, because this metal “does not degrade” and its effects are irreversible.
“We need a combination of formalization to concentrate mining in particular areas that are less vulnerable and technological improvements to reduce mercury emissions to the atmosphere.“, continues Gerson, since the socio-economic development of Madre de Dios depends on this activity.
The consequences of gold mining activity are serious, some 25,000 hectares of forest have been lost and with them a large part of the planet’s biodiversity. We are facing an environmental crime faced with the ambition of a business, more profitable than cocaine trafficking.