Szukana fraza: [Abstract = "The issues presented in this study concern a very important problem of the occurrence of cyanobacterial blooms in surface water used for water supply purposes. The objective of this study was to analyze the occurrence of cyanotoxic risk in the catchment area of the Obrzyca River \(including Sławskie lake which is the beginning of the river\), which is a source of drinking water for the inhabitants of Zielona Góra."]