This study presents the assessment of heavy metal concentrations (Cu, Cr, Co, Cd, Pb, and Ni) in the water and sediments of the Mat River. Samples were collected from five monitoring stations and analyzed to evaluate spatial distribution and to compare the aqueous phase with the sediment phase. The results indicate that metal concentrations are significantly higher in sediments than in water, highlighting the role of sediments as a long-term reservoir of pollution. In particular, copper and nickel show very high levels in sediments, while cadmium exhibits concerning values in water at some stations. The findings suggest that, despite meeting water quality standards in most cases, there is a potential ecological risk associated with sediment contamination. The accumulation of heavy metals in the sediments of the Mat River represents a potential long-term ecological risk, as these sediments may act as secondary sources of pollution during redistribution processes, such as floods or changes in the physicochemical conditions of the environment. Although the water phase currently does not show significant exceedances of standards, the presence of high levels in sediments requires continuous monitoring and further assessment of ecological and health risks. Statistical analyses and the spatial distribution of metals suggest a combination of geogenic and anthropogenic factors controlling their concentrations, with a more pronounced influence of natural processes in the upstream parts of the basin. In this context, strengthening long-term monitoring programs, incorporating biological indicators (such as benthic organisms), and developing predictive models for risk assessment under variable hydrological conditions are recommended. These measures would enable a more comprehensive understanding of pollution dynamics and contribute to the development of effective strategies for the sustainable management of the Mat River watershed.