[en] Information on the chemical and biological behaviour of plutonium and americium in the environment is increasingly needed due to the expanding production of plutonium and the high toxity of its nuclides. Only few results have been published of Pu and especially Am in brackish water columns. This paper presents determinations of sup(239,240)Pu and 241Am in water and particulate matter collected in the years 1979-1981 from the Gulf of Finland, the Baltic Sea and the Gulf of Bothnia