The high radioactivity levels in sheep in Cumbria, Scotland and Wales are due to the 1986 Chernobylaccident in the then USSR. Only 374 farms remain underrestrictions at the start of 2006, compared to 9,700 in 1986, the Food Standards Agency stated in anannual report that surveys foods for radioactive levels.
Overall, the study found that the amount of radioactivity people absorb through food in the UK remained below the EU legal limit during2005.
The report shows that in 2005, consumers' exposure to artificially produced radioactivity via thefood chain remained below the EU annualdose limit of 1 millisievert for all artificial sources of radiation.
The data are mainly used to calculate the potential dose to consumers eating locally grown foodaround the UK's nuclear sites. Other dose assessments are included for consumers in areas well awayfrom nuclear sites where sources of naturally occurring radiation are known to contribute to theradioactivity in the general diet.
The annual report is the fourth in a series produced by the agency's monitoring service. Itincludes results from the Environment Agency, the Scottish Environment Protection Agency and the Environment and Heritage Services of Northern Ireland.
It is touted by the agency as the most comprehensive annual independent report of radioactivity in food over the whole of the UK. The survey measures radioactivity from different parts of the food chain, including local food eaten by people who live close to nuclear sites.
In 1986, an accident at the Chernobyl nuclear power plant in what is now the Ukraine released large quantities of radioactivity into the atmosphere. Some of the radioactivity, predominantly radiocaesium-137, was deposited in some upland areas of the UK, where sheep farming is the primary land-use.
Due to the particular chemical and physical properties of the peaty soil types present in the areas, the radiocaesium is still able to pass easily from soil to grass. The radiocaesium then accumulates in the sheep that feeds on the grass.
The FSA has used the Food and Environment Protection Act 1985 (FEPA) since 1986 to impose restrictions on the movement and sale of sheep exceeding the limit in certain parts of Cumbria, North Wales, Scotland and Northern Ireland.
Only sheep that have less than the maximum limit of 1,000 becquerels (a measure of radioactivity) per kilogram of radiocaesium are allowed to enter the food chain under the emergency orders in theFEPA.
Initially the restricted areas were large, but have been reduced substantially as levels of radioactivity have fallen. All restrictions were lifted in Northern Ireland in 2000, the FSA stated.
In 1986, almost 9000 farms were under these restrictions in the UK. Since then, the levels of radioactivity have fallen in some of the affected areas and the number of farms still under restriction in Cumbria, Scotland and Wales now stands at 374.
Any sheep that exceed the working action level are marked with a dye and are not released from restrictions. Those that pass are allowed to enter thefood chain.
Based on a new survey results, the reports propose that none of the farms still under restriction in Cumbria and Wales should have their restrictions lifted in the near future. In Scotland, the results led to one farm being released from restrictions in January 2006.