The depth distribution of plutonium, americium, and 137Cs originating from the 1986 accident at the Chernobyl Nuclear Power Plant (***) was investigated in several soil profiles in the vicinity from Belarus. The vertical migration of transuranic elements in soils typical of the 30 km relocation area around Chernobyl *** was studied using inductively coupled plasma mass spectrometry (ICP-MS), alpha spectrometry, and gamma spectrometry. Transuranic concentrations in upper soil layers ranged from 6 × 10−12 g g−1 to 6 × 10−10 g g−1 for plutonium and from 1.8 × 10−13 g g−1 to 1.6 × 10−11 g g−1 for americium. These concentrations correspond to specific activities of 239+240Pu of 24–2400 Bq kg−1 and specific activity of 241Am of 23–2000 Bq kg−1, respectively. Transuranics in turf-podzol soil migrate slowly to the deeper soil layers, thus, 80–95% of radionuclide inventories were present in the 0–3 cm intervals of turf-podzol soils collected in 1994. In peat-marsh soil migration processes occur more rapidly than in turf-podzol and the maximum concentrations are found beneath the soil surface (down to 3–6 cm). The depth distributions of Pu and Am are essentially identical for a given soil profile. 239+240Pu/137Cs and 241Am/137Cs activity ratios vary by up to a factor of 5 at some sites while smaller variations in these ratios were observed at a site close to Chernobyl, suggesting that 137Cs is dominantly particle associated close to Chernobyl but volatile species of 137Cs are of relatively greater importance at the distant sites.
