Three toxic metals-lead, copper and zinc - were measured in the biomass of the aquatic higher plants of Elodea densa. The method of atomic absorption spectrophotometry was used. Plants were incubated at elevated concentrations of three metals in the aqueous medium. This has led to a significant increase in lead content in plant biomass. Namely, the concentration of lead in biomass increased to 1567% compared to the background concentration of this element in the biomass in the control (the background concentration was taken as 100%). After incubation, the concentration of copper in the biomass was 594% of the background concentration. After similar incubation, zinc concentration was 133% of the background concentration. The results can be useful in the analysis of biological monitoring and water purification.