Vertical distributions of (99)Tc and the (99)Tc/(137)Cs activity ratio in the coastal water off Aomori, Japan

Takahiro Nakanishi; Jian Zheng; Tatsuo Aono; Masatoshi Yamada; Masashi Kusakabe

doi:10.1016/j.jenvrad.2011.04.008

Vertical distributions of (99)Tc and the (99)Tc/(137)Cs activity ratio in the coastal water off Aomori, Japan

J Environ Radioact. 2011 Aug;102(8):774-9. doi: 10.1016/j.jenvrad.2011.04.008. Epub 2011 May 8.

Authors

Takahiro Nakanishi¹, Jian Zheng, Tatsuo Aono, Masatoshi Yamada, Masashi Kusakabe

Affiliation

¹ Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, Isozaki-cho, Hitachinaka, Ibaraki, Japan. [email protected]

PMID: 21555170
DOI: 10.1016/j.jenvrad.2011.04.008

Abstract

Using a sector-field ICP-MS the vertical distributions of the (99)Tc concentration and (99)Tc/(137)Cs activity ratio were measured in the coastal waters off Aomori Prefecture, Japan, where a spent-nuclear-fuel reprocessing plant has begun test operation. The (99)Tc concentrations in surface water ranged from 1.8 to 2.4 mBq/m(3), no greater than the estimated background level. Relatively high (99)Tc/(137)Cs activity ratios (10-12 × 10(-4)) would be caused by the inflow of the high-(99)Tc/(137)Cs water mass from the Japan Sea. There is no observable contamination from the reprocessing plant in the investigated area. The (99)Tc concentration and the (99)Tc/(137)Cs activity ratio in water column showed gradual decreases with depth. Our results implied that (99)Tc behaves in a more conservative manner than (137)Cs in marine environments.

Publication types

Evaluation Study
Research Support, Non-U.S. Gov't

MeSH terms

Cesium Radioisotopes / analysis*
Japan
Mass Spectrometry / methods*
Radiation Monitoring
Seawater / analysis
Spectrophotometry, Atomic / methods*
Technetium / analysis*
Water Pollutants, Radioactive / analysis*

Substances

Cesium Radioisotopes
Water Pollutants, Radioactive
Technetium