Soil Concentration, Vertical Distribution and Inventory of Plutonium, 241Am, 90Sr and 137Cs in the Marche Region of Central Italy

Abstract

Soil concentrations of 239+240Pu, 238Pu, 241Am, 90Sr, and 137Cs are investigated in the Marche Region of Central Italy. Mean values in uncultivated soils (0.721 +/- 0.456, 0.023 +/- 0.014, 0.241 +/- 0.165, 5.40 +/- 3.32, and 62.3 +/- 33.9 Bq kg(-1), respectively) are 3.5-8 times higher than the corresponding values in cultivated soils (0.147 +/- 0.054, 0.005 +/- 0.002, 0.047 +/- 0.021, 1.53 +/- 0.44, and 7.70 +/- 2.07 Bq kg(-1)). Radionuclide inventories and ratios are consistent with values reported by the United Nations Scientific Committee on the Effect of Atomic Radiation for this latitude (40-50 degrees N). This suggests that radiocontamination in this region is mainly due to atmospheric deposition of nuclear weapon test fallout. The vertical distribution of these radionuclides is also studied. The results show that, with the exception of 90Sr (68%), more than 90% of these radionuclides are contained in the first 20 cm of soil and that mobility follows the order 90Sr > 241Am > 239+240Pu, 238Pu > 137Cs.

Comparative migration behaviour of 90Sr, 239+240Pu and 241Am in mineral and organic soils of France

“…Although the exchangeable fraction of Am is significantly higher than for Pu (Bunzl et al, 1995), the differences in vertical migration of both actinides are often too small to be detected from ''site studies'' (Bunzl et al, 1994;Jia et al, 1999;. However, the present data underline clearly a difference between Am and Pu, especially in Vosges soil where migration rates of Am are an order of magnitude higher than those of Pu.…”

“…Radionuclide inventories and their depth profiles in soils are well documented (e.g. Mitchell et al, 1990;Mboulou et al, 1998;Jia et al, 1999;Shabana and Al-Shammari, 2001;Breban et al, 2003). The radionuclide activity ratios are usually used to trace the source (Al Hamarneh et al, 2003;Turner et al, 2003;Duffa and Frechou, 2003).…”

Vertical distribution and inventories of 137Cs in the Syrian soils of the eastern Mediterranean region

“…Most of these studies are based on processes related to Cs migration in soils, which is affected by a number of factors, such as type of soil, chemical properties, organic matter content, climatic conditions (such as rainfall, temperature, or humidity), and biological activity of microorganisms in soil (Jia et al, 1999;Kow-Ping and Chun-Nan, 1993;Mats and Bengt, 1994;Varskog et al, 1994;Sutherland, 1998;Zygmunt et al, 1998;Poreba et al, 2003). Cesium undergoes vertical and horizontal migration.…”

Application of isotope-dilution laser ablation ICP?MS for direct determination of Pu concentrations in soils at pg�g?1 levels

“…Radioanalytical techniques such as α-spectrometry or liquid-scintillation radiometry [7,8] are well established for the determination of Pu isotopes. However, they require labor-consuming sample preparation including sample digestion, leaching, and separation of plutonium by extraction chromatography followed by electroplating of plutonium on to a stainless-steel disk for α-counting.…”