Correction: Novel 90Sr analysis of environmental samples by Ion-Laser InterAction Mass Spectrometry.

Correction for 'Novel 90Sr analysis of environmental samples by Ion-Laser InterAction Mass Spectrometry' by Maki Honda et al., Anal. Methods, 2022, 14, 2732-2738, https://doi.org/10.1039/D2AY00604A.

Novel 90Sr analysis of environmental samples by Ion-Laser InterAction Mass Spectrometry.

The sensitive analysis of 90Sr with accelerator mass spectrometry (AMS) was developed to advance environmental radiology. One advantage of AMS is the ability to analyze environmental samples with 90Sr/88Sr atomic ratios of 10-14 in following a simple chemical separation. Three different IAEA samples with known 90Sr concentrations (moss-soil, animal bone, Syrian soil: 1 g each) were analyzed to assess the validity of the chemical separation and the AMS measurement. The 90Sr measurements were conducted on the AMS system VERA combined with the Ion Laser InterAction Mass Spectrometry (ILIAMS) setup at the University of Vienna, which has excellent isobaric separation performance. The isobaric interference of 90Zr in the 90Sr AMS was first largely removed by chemical separation. The separation factor of Zr in two-step column chromatography with Sr resin and anion exchange resin was 106. The 90Zr remaining in the sample was effectively suppressed by ILIAMS. This procedure achieved a limit of detection <0.1 mBq in the 90Sr AMS, which is lower than typical ß-ray detection. The agreement between AMS measurements and nominal values for the 90Sr concentrations of IAEA samples indicated that the new highly-sensitive 90Sr analysis in the environmental samples with AMS is reliable.

Use of thermal treatment with CaCl2 and CaO to remove 137Cs in the soil collected from the area near the Fukushima Daiichi Nuclear Power Plant.

A massive amount of soils and inflammable materials of plants etc. contaminated by radiocesium are generated from decontamination work in the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident affected area. In present study, the removal experiments of 137Cs in a soil collected from the FDNPP accident affected area were carried out in a lab-scale electrical heating horizontal furnace through thermal treatment with CaCl2 addition over a temperature of 900 - 1300 °C. The results indicated that the average radioactive concentration of 137Cs in the soil was 52.8 Bq/g. The removal ratio of 137Cs in the soil treated at 1300 °C was 96.3 % when 20 % CaCl2 was added. The addition of CaCl2 and CaO mixture exhibited a synergistic effect on the removal of 137Cs, relative to the addition of CaCl2 alone. Accordingly, the addition of CaCl2 or its mixture with CaO during thermal treatment is suggested to remove 137Cs in the soil collected from the FDNPP accident affected area. Additionally, segregation of the soil sample to fine and coarse fraction and then treated individually are also recommended.

Reconstruction of anthropogenic 129I temporal variation in the Japan Sea using a coral core sample.

The anthropogenic long-lived radionuclide 129I is receiving increased attraction as a new oceanic tracer in addition to usage as a fingerprint of radionuclide contamination of the marine environment. To demonstrate the robustness of 129I as an oceanic tracer in the Northwest Pacific area, specifically in the Japan Sea, the input history of 129I to surface seawater was reconstructed using a hermatypic coral core sample from Iki Island in the Tsushima strait. Iodine isotopes in each annual band were measured using AMS and ICP-MS after appropriate pre-treatments of small amounts of coral powder. The 129I/127I ratios in the 1940s were almost at background levels (<1 × 10-11) and increased abruptly in the early 1950s. Thereafter, the ratios continuously increased with some fluctuations; the maximum ratio, 7.13 ±â€¯0.72 × 10-11, being found in the late 1990s. After that period, the ratios remained nearly constant until the present time (2011). The 129I originated mainly from the nuclear weapons testings of the 1950s and the early 1960s, and from airborne releasing by nuclear reprocessing facilities. The dataset obtained here was used to construct a simple model to estimate the diffusion coefficient of 129I in the Japan Sea. The 129I/236U ratios over the observation period were also reconstructed to help constraining sources of 129I to the marine environment. Based on the results, the 129I/236U ratio obtained here could be an endmember of the water mass in the Kuroshio Current area of the Northwest Pacific Ocean.

Vaporization Mechanisms of Water-Insoluble Cs in Ash During Thermal Treatment with Calcium Chloride Addition.

The vaporization mechanisms of water-insoluble Cs in raw ash and Cs-doped ash during thermal treatment with CaCl2 addition was systematically examined in a lab-scale electrical heating furnace over a temperature range of 500-1500 °C. The results indicate that the water-insoluble Cs in the ash was associated with aluminosilicate as pollucite. Addition of 10% CaCl2 caused the maximum vaporization ratio of Cs in the raw ash to reach approximately 80% at temperatures higher than 1200 °C, whereas approximately 95% of Cs was vaporized at temperatures higher than 1300 °C when 30% CaCl2 was added. The formation of an intermediate compound, CsCaCl3, through the chemical reaction of Cs with CaCl2 was responsible for Cs vaporization by means of the subsequent decomposition of this intermediate upon the increase in temperature. The indirect chlorination of Cs by the gaseous chlorine released from the decomposition of CaCl2 was insignificant. A high CaCl2 content in the resulting annealed products with 30% CaCl2 addition delayed the decomposition of CsCaCl3 and thus lowered the Cs vaporization ratio compared to that with 10% CaCl2 addition at 900-1250 °C. Thermal treatment with CaCl2 addition is a proposed method to remove Cs from Cs-contaminated incineration ash.

Depth profile and mobility of (129)I and (137)Cs in soil originating from the Fukushima Dai-ichi Nuclear Power Plant accident.

The (129)I derived from the FDNPP accident were clearly identified near the surface and showed a trend of rapid decrease with depth. The FDNPP (129)I and (137)Cs was 51.6 ± 1.7 mBq cm(-2) and 88.2 ± 27.1 kBq cm(-2) (average of four cores inventory) respectively. On average, 91% of the FDNPP (129)I existed within the top 5 g cm(-2) and 98% within the top 10 g cm(-2) and average of 100% of the FDNPP (137)Cs existed within the top 5 g cm(-2). From the observation of the temporal variation of depth profiles from the same upland field (Kawauchi village, 20 km away from the FDNPP to the southwest direction), downward migration rates of 0.81 ± 0.32 g cm(-2) yr(-1) for the FDNPP (129)I and 0.19 ± 0.17 g cm(-2) yr(-1) for the FDNPP (137)Cs were estimated. A simple diffusion model was introduced to evaluate the downward mobility of the FDNPP-derived (129)I and (137)Cs. The apparent diffusion coefficients D of 0.0086 ± 0.0034 and 0.0011 ± 0.0010 g(2) cm(-)(4) d(-)(1) were obtained for (129)I and (137)Cs, respectively. These values might be representative for Haplic Gray lowland soils in near the steady state under humid temperate climate.

Role of endoscopic ultrasonography in the diagnosis of early esophageal carcinoma.

Endoscopic ultrasonography (EUS) for the diagnosis and staging of early esophageal carcinoma is discussed. Based on the nine-layered structure of esophageal wall, which is in good correspondence with histological layers, depth of carcinoma invasion can be investigated. Ultrasound endoscopes and probes are used for the examination. Ultrasound probes with 20 MHz and 30 MHz transducers can demonstrate the clear images of early esophageal carcinoma by using water filling method, which can discuss the change of the esophageal wall from the surface layer. Although the early esophageal carcinoma is detected by endoscopic findings with or without the dye spraying method by iodine, the diagnosis of depth of carcinoma invasion is not easy. EUS can assist in the diagnosis of depth of carcinoma invasion. Confirming the depth of carcinoma invasion by EUS and the lesion is limited to the mucosa. Endoscopists can decide the indication for endoscopic resection of the lesions.