The objective of the study has been to evaluate aquatic environment quality in Sainte-Croix Reservoir (Lake Sainte-Croix) and the Verdon River that feeds the reservoir as well as water of the Verdon River discharged from the reservoir. The evaluation was based on the accumulation of heavy metals tested in aquatic plants. The study material were water samples and aquatic plants. pH, electrolytic conductivity and metals (Cu, Cd, Pb, Zn, Ni) were determined in water. Only submerged plants were collected for testing, which was a purposeful choice because the objective was to test pollutants in the plants whose whole surface was in contact with water. The flora was dominated by the genus Potamogeton. Metal concentrations in water occurred in the following order: Pb < Cd < Ni < Cu < Zn, and in plants: Cd < Pb < Cu < Ni < Zn. The accumulation of metals according to the bioaccumulation factor (BCF) was as follows: Cu < Zn < Cd < Pb < Ni. Metal pollution indices (MPIs) for water in the test sites were: 2 < 1 < 6 < 5 < 3 < 4 < 7, and for aquatic plants: 1 < 6 < 7 < 3 < 5 < 2 < 4. These findings are typical of a number of reservoirs, and confirm their retention role. Water that feeds the reservoir has lower metal content than that in the reservoir, and the highest levels are found in the water discharged from the reservoir. A general tendency in the accumulation of metals in the reservoir is seen. It can be concluded that the reservoir may play a positive role owing to its potential accumulation capacity. Differences between the sites can be noted for all metals. Correlations between the tested parameters were determined, and the most statistically significant correlations were found between the plant species and accumulation of all the metals tested (except Zn), which was also confirmed by PCA. No statistically significant correlations were found between the concent of metals in water and in plants. Further research including analyses of the content of metals in the sediments, as well as in the immediate vicinity of the reservoir, i.e. the soil and other components of the catchment basin, planned to be carried out in the subsequent series of studies, is expected to resolve the above problem.  

25.1.2020