Comparative analysis of 239Pu, 137Cs, 210Pb and 40K spatial distributions in the top soil layer at the Baltic coast

This paper presents the results of an investigation into the spatial distribution of radionuclides of artificial (239,240Pu, 137Cs) and natural (210Pb, 40K) origins in the upper (0–5 cm) soil layers on the Baltic coastline of Lithuania (∼5 km2 area). The samples were analysed by gamma ray spectrometry and combined radiochemical procedures. The highest 210Pb, 239,240Pu and 137Cs activity concentrations were determined in the forest samples, whereas 40K activity was rather homogeneous across the study area. Relatively high 239,240Pu and 40K activity concentrations were determined along the surf zone. The 210Pb and 137Cs activity concentrations showed a gradual increase from the surf zone to the forest. The average activity concentrations of 239,240Pu, 137Cs, 210Pb and 40K in the beach and forest samples, respectively, were as follows: 0.32 ± 0.08 and 0.74 ± 0.14; 50 ± 4 and 1190 ± 50; 4.7 ± 2.0 and 48 ± 6; 186 ± 15 and 216 ± 17 Bq/kg.