Features of accumulation of heavy metals and metalloids by narrow-leaved cattail (Typha angustifolia L.) in the oxbow lake of the Sok River

The article presents an analysis of the dynamics of accumulation of heavy metals (V, Cr, Mn, Co, Ni, Cu, Zn, Rb, Sr, Cd, Pb) and metalloids (As, Se) in the aboveground and underground organs of narrow-leaved cattail (Typha angustifolia L.) in the conditions of a slow-flowing oxbow lake of the Sok River, formed during the creation of the Saratov Reservoir. The studied oxbow lake is located within the borders of the city of Samara, in its Krasnoglinsky District, where in 2021–2022 field studies were conducted and samples of bottom sediments and narrow-leaved cattail biomass were collected for subsequent laboratory study. Four sample plots were established within the studied oxbow lake for the field studies; a sample plot allocated in the coastal zone of the Saratov Reservoir, in the immediate vicinity of the studied oxbow lake, served as a control. Heavy metals and metalloids were quantified in bottom sediments, rhizomes with adventitious roots, stems, and leaves of narrow-leaved cattail using inductively coupled plasma spectrometry. Seasonal and spatial differences in the accumulation of heavy metals and metalloids by narrow-leaved cattail were identified. Most elements were more actively accumulated in the rhizome with adventitious roots (Cr, V, Co, Cu, Zn, As, Pb, Cd, Rb) compared to the stems and leaves, which were dominated by Mn and Sr. Ni and Se were practically not detected by the method used in the plant organs. The obtained data indicate that the underground organs of Typha angustifolia L. are a biogeochemical barrier for the most toxic heavy metals and metalloids in technogenically polluted low-flowing freshwater reservoirs.