Our understanding of radiation effects on the human body comes mainly from groups of people who have been subjected to high doses of radiation. The danger connected with large doses of
radiation is comparatively well documented. The potential risks connected with doses up to 200 mSv (milliSeverts) are less apparent because of the underlying incidence of cancers related to environmental and lifestyle factors.
Radiation protection standards indicate that ANY dose of radiation, regardless of how small, involves a potential risk to human health. However, current scientific evidence indicates only a minimal cancer risk or immediate effect on humans subjected to doses below 100 mSv annually, because the human body's natural repair systems are sufficient to correct radiation damage to cells soon after it happens.
radiation is comparatively well documented. The potential risks connected with doses up to 200 mSv (milliSeverts) are less apparent because of the underlying incidence of cancers related to environmental and lifestyle factors.
Radiation protection standards indicate that ANY dose of radiation, regardless of how small, involves a potential risk to human health. However, current scientific evidence indicates only a minimal cancer risk or immediate effect on humans subjected to doses below 100 mSv annually, because the human body's natural repair systems are sufficient to correct radiation damage to cells soon after it happens.
Some comparative radiation doses and their effects are listed here.
- 2 mSv/yr Typical background radiation experienced by everyone
- 1.5 to 2.0 mSv/yr Average dose to Australian uranium miners.
- 2.4 mSv/yr Average dose to US nuclear industry employees.
- Up to 5 mSv/yr Typical incremental dose for aircrew in middle latitudes.
- 9 mSv/yr Exposure by airline crew flying the New York – Tokyo polar route.
- 10 mSv/yr Maximum actual dose to Australian uranium miners.
- 20 mSv/yr Current limit (averaged) for nuclear industry employees and uranium miners.
- 50 mSv/yr Former routine limit for nuclear industry employees.
Guidelines also suggest the following:
- Allowable short-term dose for emergency workers (IAEA) - 100 mSv/yr This is the lowest level at which any increase in cancer is clearly evident. Above this, the probability of cancer occurrence (rather than the severity) is assumed to increase with dose.
- Allowable short-term dose for emergency workers in vital remedial actions - 250 mSv
- Allowable short-term dose for workers on the 2011 Fukushima accident - 250 mSv/yr
- Criterion for relocating people after Chernobyl accident - 500 mSv
- Allowable short-term dose for emergency workers taking life-saving actions - 1,000 mSv cumulative Exposure at this level would probably cause a fatal cancer many years later in 5% of persons exposed.
- A single dose of 1,000 mSv will probably causes temporary radiation sickness (Acute Radiation Syndrome) such as nausea and decreased white blood cell count, but not death.
Above this level of exposure, severity of illness and morbidity (death) increases with level of exposure.
- 5,000 mSv single dose - Would kill about half those exposed within a month.
- 10,000 mSv single dose - 100% fatality rate within a few weeks.
