RESUMEN
The temporal variation of As, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn in surface waters and sediments, and trace element accumulation and physiological changes in the macrophytes Stuckenia filiformis and Potamogeton pusillus, were estimated in the Ctalamochita River, Argentina, both upstream and downstream of Río Tercero. Chromium, Fe, Pb and Zn in surface water were higher at the downstream site, while Cu and Mn were higher upstream. Chromium, Mn and Zn in S. filiformis correlated with concentrations observed in sediments, whereas only Zn did in water. In P. pusillus, As, Co, Cr, Ni, Pb and Zn correlated with concentrations in sediments. P. pusillus revealed greater variations in the photosynthetic pigments and malondialdehyde content in the site downstream of the city than those observed in S. filiformis. Therefore, P. pusillus has a greater potential use in monitoring studies in aquatic environments with ecological risk than S. filiformis.