Americium and curium deposition in Finland from the Chernobyl accident

Abstract

Summary 241 Am and 244 Cm were analysed from peat samples collected in Finland immediately after the Chernobyl accident. The separation method included co-precipitation, anion exchange and extraction chromatography. Activities of 241 Am and 244 Cm were measured by alpha spectrometry. The activity of Chernobyl-derived 241 Am varied between 0.0115 and 9.32 Bq/m 2 and that of 244 Cm from < 0.002 to 1.97 Bq/m 2 (reference date 1.5.1986). The origin of 241 Am in Finland is predominantly from atmospheric nuclear tests. However, the geographical distribution of Chernobyl-americium is uneven and depending on a location even 100% of 241 Am in peat originated from the Chernobyl accident. The deposition pattern of Chernobyl-derived 241 Am and 244 Cm resembles that of other refractory nuclides, such as 95 Zr, 141 Ce and 239,240 Pu.