Title: Concentration levels of technetium-99 in forest soils collected within the 30-km zone around the Chernobyl reactor
Author: S Uchida, K Tagami, E Wirth, W Rühm
Reference: Environmental Pollution, Volume 105, Issue 1, April 1999, Pages 75-77
DOI:http://dx.doi.org/10.1016/S0269-7491(98)00210-3
Keywords: Technetium-99; Chernobyl accident; Forest soil; Cesium-137; ICP-MS
Abstract: Technetium-99 (99Tc) concentrations in surface soil samples collected from three forest sites within the 30-km zone around the Chernobyl reactor were determined. A simple and rapid analytical method, which consists of volatilizing and trapping Tc in a combustion apparatus, purifying the Tc with an extraction chromatographic resin and measuring it by ICP-MS, was used for the determination. The concentrations of 99Tc in the samples ranged from 1.1 to 14.1 Bq kg−1 on an air-dried soil basis. The activities of the nuclide in the soils around the Chernobyl reactor were one or two orders of magnitude higher than in other areas which were less affected by the accident. The activity ratios of 99Tc/137Cs ratios in the soils were calculated as on the order of 3.7×10−5 to 1.3×10−4.
URL: http://www.sciencedirect.com/science/article/pii/S0269749198002103
Title: Separation of Tc-99 in soil and plant samples collected around the Chernobyl reactor using a Tc-selective chromatographic resin and determination of the nuclide by ICP-MS
Author: Uchida, S.; Tagami, K.; Ruhm, W.; Steiner, M.; Wirth, E.
Reference: Applied Radiation and Isotopes, July-Aug. 2000, vol.53, no.1-2, pp. 69-73
DOI: http://dx.doi.org/10.1016/S0969-8043(00)00112-3
Keywords: Technetium-99; Chernobyl fallout; Organic soil; Plants of the understorey vegetation
Abstract: Technetium (Tc) is known to have high mobility in a soil–water system and also high bioavailability for plants, because the most stable form of Tc in natural surface environment is thought to be TcO−4 which is highly soluble. The chemical form of Tc, however, changes with environmental conditions. Thus, it is necessary, for realistic assessment, to obtain transfer parameters, such as transfer factors, under natural conditions. However, it is difficult to obtain these parameters using global fallout in actual fields due to its low concentration. In this study, concentrations in surface soil and plant leaf samples collected from forest sites within the 30-km zone around the Chernobyl reactor were measured for the first time. In the case of soil samples, a simple and rapid analytical method for determination of is used which consists of volatilizing and trapping Tc in a combustion apparatus, purifying the Tc with an extraction chromatographic resin, and measuring it by inductively coupled plasma mass spectrometry (ICP-MS). For plant samples, a wet digestion method in combination with the resin is applied and the is measured by ICP-MS. Concentrations of in organic soil samples and leaves of strawberry (Fragaria vesca) range from 1.1–14.8 Bq kg−1 dry weight and 0.2–6.0 Bq kg−1 dry weight, respectively. Our results indicate that soil-to-plant transfer factors for Tc are similar to those for Cs.
URL: http://www.sciencedirect.com/science/article/pii/S0969804300001123
