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More controversial health efffects

The bystander effect

You may think that if radiation caused ionization in a particular cell then only that cell would be damaged.  However there is evidence that nearby cells are also damaged even though there was no ionization in them.

This is called the ‘bystander effect’ and may be due to the way chemical messages are sent between cells.

Try Why Do Astronauts Float by Julian Hamm

Genomic instability

You may also think that if DNA in a cell was damaged but not in a way to cause cancer then you would get away with it.

But when this cell divides its damaged DNA is replicated in the daughter cells.  This damaged DNA continues to be replicated down the generations.  The DNA damage is added to by random mutations that happen in DNA all the time.

This may make it more likely for accumulated random mutations in future generations of cells to become cancerous.  The genetic information stored in your DNA is called your genome.  So this type of damage is called ‘genomic instability’.

It is possible that genomic instability is the cause of most cancer attributed to low doses of radiation.

Other possible health effects

Radiation is not just associated with cancer.

Radiation damages the immune system.  This may increase the risk of heart attacks years after exposure.  It may also increase the risk of certain diseases to do with digestion and breathing.

Radiation can make you sterile.  Some children exposed to radiation before they were born show impaired growth and development.  There is some evidence that these children’s chances of getting cancer in later life also increase.

Most of these effects seem to be random like cancer rather than certain like radiation sickness.

back to Lesson 5: How Radiation Harms