EN
The first estimate of diatom indicatory values in Poland is presented. It comprises 455 diatom taxa occurring in ten ecologically different ecosystems: four rivers of various type and degree of pollution, limnocrenic and salty springs, oligotrophic springs, a dam reservoir, a brown coal excavation pit and a peat excavation pit. Indicatory values are used to describe saprobity, trophic conditions, tolerance for pollution, oxygen demand, water alkalinity pH, salinity, distribution and abundance. The compiled list of diatoms contains information about the conditions that are preferred by a given species, consequently, it may constitute a basis for the biological assessment of water quality.