A note on 207Bi in environmental samples

Traces of the radionuclide 207Bi were identified in soil and cryoconite (glacier sediment) samples from Alpine regions of Austria. This nuclide has been produced in thermonuclear explosions mainly in the early 1960s and subsequently dispersed in the atmosphere. Activity concentrations up to 22 Bq/kg d.m. have been found. The ratio 207Bi:137Cs(global fallout) equals (1.70 ± 0.12)10−3, which is in accordance with literature data. When low levels of 207Bi are assessed by gamma spectrometry, corrections must be made for a gamma line produced in the lead shield by neutron activation due to cosmic neutrons.