Environmental Effect on Metals Accumulation in Aquatic Plants of Belarusian Lakes and Rivers

The accumulation of metals by macrophytes varies depending on the biological state of organisms (species, size, and age) as well as numerous environmental factors, of which temperature, pH, concentration, and chemical properties of the elements are most common. The aim of the study is to identify the environmental factors influencing the content of heavy metals (Mn, Cu, Pb) in the submersed macrophytes tissues within Belarusian reservoirs and rivers. The importance of factors such as pH, total water mineralization, lake trophic level, Mn, Cu, and Pb concentrations in water, and bottom sediment has been evaluated. The National Environment Monitoring system data have been used in the study. As many as 387 higher aquatic plant samples from lakes and rivers on the territory of Belarus from 2000 to 2020 were tested. Measurements of Mn, Cu, and Pb concentrations were performed using emission spectral analysis methods. The obtained values were statistically processed using correlation and variance analysis. Statistically significant relationships between Mn content in the macrophytes tissues and lake and river bottom sediments have been established (r = 0.26–0.52; p < 0.001). The pH influence on Pb content in the submersed macrophytes has been revealed (r = − 0.37; p < 0.001). As the pH value is getting decreased, the Pb content is getting increased. The strongest correlation has appeared for a subsample limited to pH < 6.5 (acidic and slightly acidic waters), the value of the correlation coefficient is − 0.6. Such a parameter as total water mineralization (mg/dm3) affects Mn accumulation in the submersed river macrophytes (r = 0.45; p < 0.001). A fairly complete picture of the ecological conditions for the growth of macrophytes gives the degree of trophic water bodies. Statistically significant differences in Mn and Cu contents in the tissues of plants growing in lakes of varying trophicity have been established (Kruskal–Wallis H-test = 16.9–16.2; p = 0.001–0.007). The lowest concentration of Mn has been observed in plant tissues of mesotrophic lakes with signs of oligotrophy. Estimation of the environmental factors impact on metals accumulation in aquatic plants tissues can be effectively used in water bodies ecological status determination.