Metals in organs of bottom sediments and aquatic plants of the Ełk River and its tributaries

The aim of the work was to analyze the content of Ni, Pb and Cd in organs (root, stem, leaf) Typha latifolia L. and Nuphar lutea as well as bottom sediments of the Ełk River and selected tributaries. An attempt was also made to indicate the factors and processes governing the behavior of the investigated metals in the water environment of the examined rivers. The research object was the Ełk River with its three tributaries - the Gawlik River, the Binduga River and the Kuwasy Canal. Samples of bottom sediments, leaves, stems and roots of Typha latifolia L. and Nuphar lutea were collected in August of 2015. The content of metals was determined by flame atomic absorption spectrometry (F-AAS). The results of analyses of sediments and plant material indicate a lack of environmental pollution by nickel (2.58-8.50 mg-kg-1) and lead (3.82-15.99 mg-kg-1) of the Ełk River and its tributaries whereas the cadmium content ranged from 0.16-0.76 mg-kg-1. Nuphar lutea and Typha latifolia L. showed a varied capacity to accumulate nickel (1.20-10.51 mg-kg-1) and lead (0.04-14.16 mg-kg-1), occurring primarily in the roots. The smallest concentration of nickel and lead was recorded in the stems. The highest concentration of cadmium (2.56 mg-kg-1) was noted in the roots and the lowest (0.01 mg-kg) in the leaves. Factor analysis pointed to the processes of mobilizing elements from bottom sediments as a result of pH drop and their uptake by macrophyte roots and sorption processes of metal ions by macrophytes from river waters and their intensive accumulation in bottom sediments.