Table 1

Illustrative radiation exposures from natural background, medical, routine nuclear operations and Chernobyl with hypothetical lifetime risks.

Exposure scenario

Exposure

Mortality risk+

Notes


Examples of radiation exposures not due to Chernobyl

General population (background exposures)


UK average (natural + medical)

200 mSv

1 %

Lifetime (~75 yr) exposure to 2.7 mSv yr-1 UK average annual dose.

Exposure at UK limit for radon exposures in the home [49]

750 mSv

3.7 %

Lifetime (~75 yr) exposure to UK limit 200 Bq m-3 radon gas ≈ 10 mSv yr-1 dose. Above this limit, action must be taken to reduce radon in houses in the UK. Dose depends on time spent at home and doses at this high rate are rare.


Working population (above background)*


UK average for classified radiation workers [50]

18 mSv

0.07%

Average current dose (above background) of classified workers in the nuclear industry of 0.6 mSv yr-1 accumulated over a 30 year working period.

Long haul air crew [51]

135 mSv

0.54%

Typical exposures in the range 3–6 mSv yr-1: assume 4.5 mSv yr-1 over 30 yrs


Exposures after Chernobyl (above background)*

General population


Residents of "strict control zones" (areas > 555 kBq m-2 137Cs).

50 mSv

0.25%

Accumulated dose for approximately 10 year period after the accident [37, 52]

Annual dose limit to populations of the Chernobyl affected areas, 1990's

75 mSv

0.37%

If external + internal dose exceeded this limit, measures had to be taken to reduce dose. Accumulated dose at 1 mSv yr-1 over 75 yr lifetime [53]

Consumer of sheep meat from the most contaminated areas in the UK

4.1 mSv

0.02%

Consumption (at a high rate) of lamb from farms most affected by Chernobyl for 75 year period (assumed mean 137Cs = 500 Bq kg-1 in 1986, declining with effective half life 25 yr). Over-estimate of likely real exposures.


Working population


Unofficial residents of the 30-km exclusion zone. In late 1990's range of doses in a number of villages [2], Ukrainian sector 30 km zone was 1–6 mSv y-1

255 mSv

1.0%

Illustrative of higher exposures: person of working age (25) who received 100 mSv during period to 1995, then returned to Zone in 1996 and received 6 mSv yr-1 in 1996 declining (with effective half life 25 years) to age 75 in 2036. N.B. some (uninhabited) areas of the Zone would give much higher doses.

Chernobyl emergency workers [37]:

Average

High dose group

100 mSv

250 mSv

0.4%

1.0%

Accumulated risk from exposures during 1986–87. Does not include very high exposures to those who suffered from ARS. Working population.


+ A DDREF of 2 is applied for these (relative to the Japanese bomb survivors) low dose rate exposures. If the DDREF were not used all the risk factors would increase by a factor of 2. * These exposures are in addition to those from background radiation. Note that exposures to the 134 ARS victims and doses to the thyroid following Chernobyl are not included here (see text).

Smith BMC Public Health 2007 7:49   doi:10.1186/1471-2458-7-49

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