1. Department of Physical Geography and the Environmental Management , University of Gdańsk , Bażyńskiego 4, 80-309 Gdańsk , Poland
2. Department of Analytical Chemistry , Gdańsk University of Technology Narutowicza 11/12G, 80-952 Gdańsk , Poland
3. Department of Limnology , University of Gdańsk , Bażyńskiego 4, 80-309 Gdańsk , Poland