Establishing rapid analysis of Pu isotopes in seawater to study the impact of Fukushima nuclear accident in the Northwest Pacific

• Published in: Scientific reports 2018-01, Vol.8 (1), p.1892-11, Article 1892
• Main Authors: Men, Wu, Zheng, Jian, Wang, Hai, Ni, Youyi, Aono, Tatsuo, Maxwell, Sherrod L., Tagami, Keiko, Uchida, Shigeo, Yamada, Masatoshi
• Format: Article
• Language: English
• Subjects: 639/638/11/296; 704/172/169/895; 704/172/4081; Chemical analysis; Chemistry Techniques, Analytical - methods; Contamination; Decontamination; Fluorides - chemistry; Fukushima Nuclear Accident; Humanities and Social Sciences; Isotopes; Isotopes - chemistry; Lanthanum - chemistry; Limit of Detection; multidisciplinary; Nuclear accidents & safety; Plutonium; Plutonium - chemistry; RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; Radiation Monitoring - methods; Science; Science (multidisciplinary); Seawater; Seawater - analysis; Water analysis; Water Pollutants, Radioactive - chemistry
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-20151-4

In order to assess the impact of the Fukushima derived Pu isotopes on seawater, a new analytical method to rapidly determine Pu isotopes in seawater by SF-ICP-MS including Fe(OH) 2 primary co-precipitation, CaF 2 /LaF 3 secondary co-precipitation and TEVA+UTEVA+DGA extraction chromatographic separation was established. High concentration efficiency (~100%) and high U decontamination factor (~10 7 ) were achieved. The plutonium chemical recoveries were 74–88% with the mean of 83 ± 5%. The precisions for both 240 Pu/ 239 Pu atom ratios and 239+240 Pu activity concentrations were less than 5% when 15 L of seawater samples with the typical 239+240 Pu activity of the Northwest Pacific were measured. It just needs 12 hours to determine plutonium using this new method. The limit of detection (LOD) for 239 Pu and 240 Pu were both 0.08 fg/mL, corresponding to 0.01 mBq/m 3 for 239 Pu and 0.05 mBq/m 3 for 240 Pu when a 15 L volume of seawater was measured. This method was applied to determine the seawater samples collected 446–1316 km off the FDNPP accident site in the Northwest Pacific in July of 2013. The obtained 239+240 Pu activity concentrations of 1.21–2.19 mBq/m 3 and the 240 Pu/ 239 Pu atom ratios of 0.198–0.322 suggested that there was no significant Pu contamination from the accident to the Northwest Pacific.