Introduction: Heavy metal contamination of water bodies poses an environmental risk, especially in high-mountain ecosystems that serve as basin headwaters. Sediments play a crucial role since they accumulate various elements that can be released into the water, affecting the quality of the aquatic environment. Many studies do not distinguish between pollution sources in tributaries/effluents and in lakes, which limits precise identification of their origins and behaviour and hinders effective pollution management.
Methods: The objective of this study was to determine the origin of chemical elements in the tributaries/effluent and interior of a high Andean lagoon. Metal samples (Fe, Al, Zn, Cu, Pb, Cr, Ni, As, Cd, and Hg) were collected, and principal component analysis (PCA) was used to identify sources of contamination.
Results: In the tributaries and effluent, Fe, Al, and Zn presented the highest concentrations, with Hg, Cd, and As amounts exceeding the risk thresholds at several points, especially Hg and Cd in the Vilque River. In the lagoon, significant accumulation of Hg and Cd was detected near the tributaries, and high concentrations of As were detected in several areas. The PCA explained 91.65% of the variance, differentiating anthropogenic sources (Hg, Cd, Cu, Zn) from natural sources (Al, Cr, Fe, Ni).
Conclusion: Tributaries transport pollutants, facilitating the accumulation of Hg and Cd in lagoon sediments. The results provide a better understanding of the behaviour of metals in the ecosystem and contribute to environmental management.