Worker doses and potential health effects resulting from the accident at the Fukushima nuclear power plant in 2011

Abstract

Purpose: The reliability of exposure scenarios used in the World Health Organization's Health Risk Assessment (HRA) for Fukushima workers was examined. HRA risk estimates for cancer incidence in these workers were then reviewed.

Materials and methods: The HRA constructed four exposure scenarios to estimate worker radiation doses; recent individual dosimetric data were used to assess their reliability. Risks of specified cancer types attributable to radiation exposure were estimated in the HRA by calculating Lifetime Attributable Risks (LAR) for each scenario, and comparisons of LAR are provided.

Results: The scenarios were confirmed as reliable for the purposes of the HRA. For the lowest dose scenario (Scenario 1: 69% of the workforce), the HRA found that any elevated cancer risk was insignificant. Significantly elevated cancer risks were, however, found for the three higher dose scenarios.

Conclusions: For the highest dose scenario (Scenario 4: 13 workers), LAR values for thyroid cancer up to 3.5% were estimated, but a radiation-related increase in thyroid cancer incidence is unlikely to be observed because of the small number of workers. For the two intermediate dose scenarios, a small number of cancer cases may occur, but these are unlikely to be observed because the variability in baseline rates of cancer incidence is much larger than the predicted radiation-related incidence rates.

Keywords::

• Dosimetry
• effects
• workers
• accident
• Fukushima

Acknowledgements

The authors wish to acknowledge the contributions of members of the WHO International Expert Working Group: Dr Makoto Akashi (National Institute for Radiological Sciences (NIRS), Japan), Dr Lynn Anspaugh (Univ. of Utah, USA), Dr Nick Gent (PHE, UK) and Dr Dominique Laurier (Institut de Radioprotection et de Sûreté Nucléaire (IRSN), France), as well as the invaluable assistance of Dr Shin Saigusa (NIRS, Japan).

Declaration of interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.