Radionuclides

When a situation arises that leads to levels of radioactivity in food that are higher than natural background levels, there is EU-wide legislation to limit exposure.

Natural levels of radioactivity in food are extremely low and there is normally no specific legislation prescribing limits for radionuclides in food. However, in the case of a nuclear accident or radiological emergency, Council Regulation (Euratom) 2016/52 becomes active. This requires that special legislation is issued setting maximum permitted levels of radionuclides in food as per the table below.

Nuclides Maximum permitted level (Bq/kg)

Isotopes of strontium, notably Sr-90

750

Isotopes of iodine, notably I-131

2000

Alpha-emitting isotopes of plutonium and transplutonium elements, notably Pu-239 and Am-241

80

All other nuclides of half-life greater than 10 days, notably Cs-134 and Cs-137

1250

The Commission then consults with experts and, preferably within a month of adopting the special conditions Regulation, brings out a second Regulation either confirming or adapting the provisions of the first Regulation.

In addition to Council Regulation (Euratom) 2016/52, there are 2 other Regulations that refer to radioactive contamination of foods:

  • Regulation 2219/89 lays down the conditions for exporting food and feed after a nuclear accident or radiological emergency. Food and feed with levels of radioactive contamination that exceeds permitted levels may not be exported from member states.
  • Regulation 737/90 applies to agricultural products originating in third countries that are affected by the Chernobyl accident.

 

Special measures following Fukushima

There is extra legislation in place following the Fukushima incident of 2011. This imposes special conditions on feed or food originating in or consigned from Japan. The current regulation on this is Implementing Regulation 2016/6, amended most recently by Implementing Regulation 2017/2058, and the table below outlines the limits applicable to seafood:

Nuclides Maximum permitted level in seafood (Bq/kg) Maximum permitted level in food intended for infants and young children (Bq/kg)

Sum of caesium-134 and caesium-137

100

50

 

Monitoring Radioactivity in the UK

The major producers of radioactive waste in the UK are required to monitor the environment around their premises. The Environment Agency, the Food Standards Agency, the Northern Ireland Environment Agency and the Scottish Environment Protection Agency work together on monitoring programmes to measure radioactivity in the environment and in food. Their results are brought together annually in the Radioactivity in Food and the Environment (RIFE) report. The risk to public health of any radioactivity detected is assessed in the report.

The levels set in Regulation 2016/52 are based on the assumption that a person consuming a diet containing 10% of food contaminated at the maximum level will, over one year, receive a dose of ionising radiation of 1 millisievert (mSv) - the acceptable annual dose limit for a human being.

More information about radioactivity in food can be found in this Food Standards Agency page; the latest RIFE report is available here.

 

How safe are the limits?

The levels set in Regulation 2016/52 are based on the following assumption: A person consuming a diet containing 10% of food contaminated at the maximum level will, over one year, receive a dose of ionising radiation of 1 millisievert (mSv). 1 mSv corresponds to the acceptable annual dose limit for a human being; the potential dose of 1mSv from the diet will be in addition to any other ionising radiation, natural or otherwise, received by that person.

 

Notes on the units used to describe radioactivity

The limits are set in Bq/kg (becquerel per kilogram). A becquerel is an amount of radiation emitted equal to the number of disintegrations per second the radionuclide undergoes. Roughly speaking, the more becquerels, the more the harmful radiation, but this may be misleading, because there are different types of radiation (alpha, beta, gamma and neutron radiation), each with its own adverse health effect. In addition, the health effect depends on prameters such as the food, its consumption and the age of the consumer.

One millisievert (1 mSv) corresponds to the acceptable annual dose limit for a human being. The sievert is a derived unit that describes a dose of radiation in terms of the biological effect that it has on the human body. The definition of the sievert depends on the relationship between the radiation and the effect on the human body, and is determined by the International Commission on Radiological Protection.