Radioactivity in food: your questions answered

Last updated:
18 April 2011
Answers to some of your most frequently asked questions about radioactivity in food.

Are we protected from unsafe levels of radiation?

Yes. In the UK, strict legal controls govern how radioactive waste is disposed of and outline the acceptable levels of radiation found in people.

Does radioactivity occur naturally in food?

Yes. There are some common sources of natural radioactivity in food, one of which, for example, is a component of potassium called potassium 40. It forms 0.012% by weight of all natural potassium and occurs in the cells of all living things.

Natural radioactivity can also be transferred to crops from rocks and minerals present in the soil, while drinking water can pick up radioactivity from the earth, and fish and shellfish can take up radioactivity from the water or sea floor.

Artificial radioactivity can get into food after it has been discharged into the environment from civil or military nuclear operations. It then passes through the food chain in the same way as natural radioactivity.

How is it calculated?

A radiation dose is called a sievert, normally measured in thousandths (millisieverts) or even millionths (microsieverts) because most radiation in the environment is so small.

How is radioactivity monitored in food?

The major producers of radioactive wastes must monitor the environment around their site, while the Government carries out secondary checks.

In addition, the levels of radioactivity in milk are closely watched, because this is a highly effective way to measure radioactivity around nuclear sites. Most sites have grazing cows nearby – radioactive elements they might ingest will usually pass into their milk.

The same goes for fish and shellfish, which are monitored after being caught.

Routine monitoring for all food is also carried out at points of entry to the UK.

What does radioactivity do to us?

Radioactivity can damage our body's DNA, a complex molecule found in all our cells that controls their function and growth. Low radiation doses can be repaired but higher doses can change our body's cells. In these cases cancer can develop.

Large radiation doses kill cells. Radiotherapy, for instance, uses radiation to target and destroy tumour cells while at the same time minimising damage to normal tissue.

Does the Food Standards Agency assess radioactive waste and food safety?

The Agency assesses the food safety implications of proposed discharges of radioactive waste. It does this on behalf of the Environment Agency (for England and Wales) and the Scottish Environment Protection Agency (for Scotland) as part of their considerations for granting of Permits (in England and Wales) and Authorisations (in Scotland) to discharge radioactive wastes from nuclear sites.

Expert scientific advice on the effects of radioactive material on people is provided to the Agency by the Radiological Protection Division of the Health Protection Agency.