engleski

Selenium distribution in water biotopes of Kopački Rit floodplain

Selenium is a widely distributed element generally found in low concentrations in the environment. Anthropogenic activities contribute to elevated content of selenium in aquatic ecosystems, while its accumulation, especially in floodplain systems, is under-investigated. The physico-chemical water properties, selenium concentration in water, sediment and biota as well as the composition and abundance of phytoplankton and periphytic algae were investigated in July 2016, in the Danube River, Sakadaš Lake and the channel located near the farm Eblin (Kopački Rit floodplain). In the conditions of high water level more comparable concentrations of nutrients were found between river and lake water (total nitrogen: 7.57 - 9.31 mg/L, total phosphorus: 2.77 to 2.82 mg/L, nitrates: 5.87 - 6.77 mg N/L). Low selenium content in water and sediment was found in all localities, with the highest concentration in the river sediment (0.256 ± 0.012 mg/kg). Higher selenium concentrations were found in plankton samples (Danube River: 0.385 ± 0.013 mg/kg, Sakadaš Lake: 0.332 ± 0.098 mg/kg). At all localities the diatoms dominated in phytoplankton, while cryptophytes, green algae and cyanobacteria were abundant in the lake and the channel. Selenium concentration in metaphyton, macrophytes (white water-lily, yellow pond-lily, fringed water-lily, common frogbit, common reed, cattail) and periphyton on different substrates varied considerably, while the lowest value was recorded in cattail leaves (0.014 ± 0.004 mg/kg), and the highest in metaphyton (0.277 ± 0.012 mg/kg). The variations in selenium content in different components of aquatic systems indicate the importance of investigating the distribution of selenium in water biotopes.

floodplain ; selenium ; macrophytes ; phytoplankton ; periphyton

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