A recent study has revealed that certain Amazonian trees can function as natural sensors to track mercury contamination derived from illegal gold mining.
The Ficus insipida, a common tropical species in Latin America, has the ability to accumulate mercury in its growth rings. This allows for documenting exposure to this heavy metal over decades.
Illegal Mining and its Impact in Madre de Dios
The research was conducted in Madre de Dios, a Peruvian region with one of the largest illegal mining industries in the world.
Between 100,000 and 200,000 informal miners use mercury to separate gold from mud, generating a silent environmental crisis.
Trees analyzed in areas near amalgam burnings, such as Boca Colorado and Laberinto, showed high levels of mercury. This is in contrast to more distant localities like Boca Manu and Chilive.
The Potential of Ficus insipida as an Environmental Record
The study, led by Jacqueline Gerson from Cornell University (USA), analyzed several tree species, but only Ficus insipida presented well-defined growth rings, ideal for use as environmental archives.
These trees allow for storing annual data on terrestrial pollution, a less explored aspect compared to effects on aquatic ecosystems.
Challenges and Next Steps
Researcher David M. Lapola from the State University of Campinas (Brazil) warned that although the study demonstrates the feasibility of the method, it is still necessary to understand how the distance to mining activity and its contamination influence the mercury accumulation in trees.
The finding offers an effective and low-cost alternative for monitoring pollution in hard-to-reach areas, as the metal is absorbed by the leaves and stored in the trunk through the phloem.
A Key Tool to Address Environmental Challenges
While the physiological process is not yet fully understood, Jacqueline Gerson concludes that the information collected using this method can facilitate regional monitoring strategies, contributing to the fight against one of the major environmental issues in the Amazon.
