EN
This paper reports the results of studies of organic carbon concentrations (TOC, DOC and POC) in samples of natural water. The material studied came from 11 lakes in Wielkopolski National Park, from the Vistula and Warta rivers, 20 public wells situated in rural areas of the Wielkopolska region, and mineral water intakes located at different depths. In the case of surface waters, changes in DOC and POC were recorded for one year. The results were compared with data on natural waters available in literature.