Studies of Lead-210 in Air and Natural Soils in Estonia

摘要

Lead-210 in Estonian air and soil was studied using HPGe γ spectrometric analysis. In 2001-2005 weekly 210Pbconcentrations in surface air varied in the range from 0.09 mBq m-3 to 2.8 mBq m-3 with the country-wide mean value of 0.47mBq m-3. High 210Pb air concentrations in winter and low values in late spring and early summer were the dominant seasonalvariation trends. 210Pb activity concentrations in air were negatively correlated with air temperature and wind speed.Unsupported fraction in soil profiles was derived from depth-dependent 210Pb activity concentrations using the diffusionmodel and the compartmental model. The annual average atmospheric deposition flux of 210Pb for natural sites of 164 Bqm-2a-1 and its deposition velocity of 0.010 m s-1 were evaluated. The migration velocities of unsup ported 210Pb from surface intodeeper soil layers were in the range from 2.7 mm a-1 to 3.0 mm a-1.