Учебное пособие Казань-2016 Сайфуллина М. Н., Хабирова Н. М. English for Physicists



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Posobie dlya fizikov Habirova Sajfullina ispravv

The effects on human health 
There are two main health effects caused by radiation, which act over 
the short- and long-term and also at shorter and greater distances. Radiation 
causes health problems by killing cells in the body, and the amount and type 
of damage done depends on the dose of radiation received and the time over 
which the dose is spread out. 
The dose limits for emergency workers in the event of a nuclear 
accident are 100 mSv if protecting property or 250 mSv in a life-saving 
operation. Between that upper limit and 1 Sv received within a single day, 
exposure is likely to cause some symptoms of radiation poisoning, such as 
nausea and damage to organs including bone marrow and the lymph nodes. 
Up to 3 Sv these same effects are more serious with a likelihood of 
acquiring infections due to a reduced number of white blood cells in the 
body – with treatment, survival is probable but not guaranteed. 


97 
Larger doses will, in addition to those symptoms above, cause 
hemorrhaging, sterility and skin to peel off; an untreated dose of more than 
3.5 Sv will be fatal, and death is expected even with treatment for doses of 
more than 6 Sv. The radiation level decreases with the square of the
distance from its source, so someone twice as far away from an external 
source will receive a quarter of the radiation. 
Receiving a high dose in a shorter time usually causes more acute 
damage, as greater doses kill more cells, while the body can have had time 
to repair some damage with more time having elapsed between doses. 
However, radioactive material that is spread to a wider area can cause 
longer-term health effects via prolonged exposure, particularly if they enter 
the food chain or are inhaled or ingested directly. Taking radioactive 
materials into the body also presents the greatest danger from atoms that 
undergo alpha-decay, as alpha particles are not very penetrative and are 
easily absorbed by a few centimeters of air. 
Radioactive isotopes of iodine, which undergo beta-decay, can build up 
in the thyroid gland and can cause thyroid cancer. Attempts to prevent this 
involve distributing pills that include nonradioactive iodine-127 and which 
flood the thyroid, preventing uptake of radioactive iodine. For one-off 
doses, such as those from medical scans, the risk of later developing cancer 
is estimated at around 1 in 20 000 per mSv received. Absorbing an 
accumulated dose of 1 Sv over a longer period of time is estimated to 
eventually cause cancer in 5% of people. However, there is disagreement 
over whether very small doses comparable to the level of background 
radiation actually contribute to health effects. 
(Adopted from 
www.iop.org 

 
 
 
 


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