Scientific expedition in the Amazon: Exploring the behavior of Rare Earth Elements in brazilian rivers

Last month, we carried out the second field campaign of our research project in Manaus, aiming to deepen our understanding of the behavior of rare earth elements (REEs) in the rivers of the Brazilian Amazon. The study focuses on the determination, fractionation, and speciation of REEs, elements that are crucial to many modern technologies, yet still poorly understood in complex tropical environments such as those found in the Negro, Solimões, and Amazon river basins.

The campaign brought together an international and multidisciplinary team. Representing Montanuniversität Leoben (Austria), we had Antonia Siebenbrunner, Johanna Irrgeher, Stefan Wagner, and Thomas Prohaska, all from the Department of General and Analytical Chemistry. From the GEMB, José Lucas Martins Viana and Luiz Felipe Pompeu Prado Moreira took part. Local expertise was provided by Ézio Sargentini and Marcos Bolson from the National Institute of Amazonian Research (INPA). The team also included colleagues from Queen’s University Belfast, such as Paul Williams and Brian Quinn.

Throughout the campaign, we collected water and sediment samples at strategic locations, including the famous Meeting of the Waters, where the Negro and Solimões rivers flow side by side without immediately mixing, a natural phenomenon that provides ideal conditions for studying biogeochemical transitions. We also explored the potential of passive sampling techniques, an innovative and promising approach for long-term environmental monitoring in remote regions.

We are especially grateful for the essential support provided by the local boat operators (barqueiros), whose deep knowledge of the rivers and navigation experience were fundamental to the success of this field campaign. Without their guidance, dedication, and skill, it would have been impossible to access many of the sampling sites or carry out our work with such precision and safety.

Although this was the final field campaign of the current project, it marks only the beginning. The success of this effort lays a solid foundation for future scientific collaborations and ongoing studies. Understanding the behavior of REEs in Amazonian ecosystems is vital for improving environmental monitoring, supporting sustainable water management, and enhancing climate change adaptation strategies.

This work is funded by FAPESP and supported by the Erasmus program, highlighting the importance of global scientific exchange in addressing local environmental challenges.