The species Zannichellia palustris and Myriophyllum acuatium, collected along the Loa River basin, North Chile, were chosen as possible bioindicators for Cd, Pb, and Cu. These species have a cosmopolitan distribution and can survive very sudden and large fluctuations in salinity. They are widely spread in Chile and in spite of their enormous salt tolerance they seldom penetrate to the marine habit. 	Quantification in water and algae samples was made by Differential Pulse Anodic Stripping Voltammetry (DPASV) after UV (water) and open wet digestion (algae). The cadmium concentrations found in algae samples ranged from 0.72±0.01 to 32±0.31 µg/g d.w. Values for lead were less and estimated 0.4±0.01 to 2.13±0.08 µg/g d.w.. Copper concentrations were between 13±0.2 and 119±0.5 µg/g d.w.. In comparison with the element concentrations in the water samples, a significant biomagnification, especially for cadmium in Myriophyllum acuatium was observed