title: Assessment of the risk of medium-term internal contamination in Minamisoma City, Fukushima, Japan, after the Fukushima Dai-ichi nuclear accident.
abstract: BACKGROUND
  The Fukushima Dai-ichi nuclear disaster, the first level-7 major nuclear disaster since Chernobyl, raised concerns about the future health consequences of exposure to and intake of radionuclides. Factors determining the risk and level of internal radiation contamination after a nuclear accident, which are a key to understanding and improving current nuclear disaster management, are not well studied.
  
  
  OBJECTIVE
  We investigated both the prevalence and level of internal contamination in residents of Minamisoma, and identified factors determining the risk and levels of contamination.
  
  
  METHODS
  We implemented a program assessing internal radiation contamination using a whole body counter (WBC) measurement and a questionnaire survey in Minamisoma, between October 2011 and March 2012.
  
  
  RESULTS
  Approximately 20% of the city's population (8,829 individuals) participated in the WBC measurement for internal contamination, of which 94% responded to the questionnaire. The proportion of participants with detectable internal contamination was 40% in adults and 9% in children. The level of internal contamination ranged from 2.3 to 196.5 Bq/kg (median, 11.3 Bq/kg). Tobit regression analysis identified two main risk factors: more time spent outdoors, and intake of potentially contaminated foods and water.
  
  
  CONCLUSIONS
  Our findings suggest that, with sensible and reasonable precautions, people may be able to live continuously in radiation-affected areas with limited contamination risk. To enable this, nuclear disaster response should strictly enforce food and water controls and disseminate evidence-based and up-to-date information about avoidable contamination risks.
authors.affiliation: Department of Global Health Policy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Amina
authors.initials: A
authors.lastname: Sugimoto
authors.forename: Stuart
authors.initials: S
authors.lastname: Gilmour
authors.forename: Masaharu
authors.initials: M
authors.lastname: Tsubokura
authors.forename: Shuhei
authors.initials: S
authors.lastname: Nomura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kami
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Oikawa
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kanazawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Shibuya
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005507:Food Contamination, Radioactive; D062406:Fukushima Nuclear Accident; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D011829:Radiation Dosage; D011834:Radiation Monitoring; D018788:Radioactive Hazard Release; D011868:Radioisotopes / Q000032:analysis*; D012307:Risk Factors; D014875:Water Pollutants, Radioactive; D055815:Young Adult
chemical_list: D011868:Radioisotopes; D014875:Water Pollutants, Radioactive