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The information in the archive was published by MAFF, Department of Health and the Scottish Executive before April 1st 2000 when the Food Standards Agency was established.

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Food Surveillance Information Sheet

Number 183     July 1999


Index to MAFF UK Food Surveillance Information Sheets, 1999

See also:
102: MAFF, UK - Undeclared Irradiation of Foodstuffs Surveillance Exercise (March 1997)
108: MAFF UK - A Survey of Radiocaesium Contamination Levels and Estimations of Dietary Intake of Edible Wild Fungi (June 1997)
109: MAFF UK - A Survey of Natural Radionuclides in UK and European Beers (June 1997)
110: MAFF UK - A Survey of Levels of Radioactivity in UK Produced Beverages (June 1997)
153: MAFF UK - Assessment of the Potential Variability of Naturally Occurring Radionuclides in Foodstuffs Produced in the UK (July 1998)
199: MAFF UK - Multi-Element Survey of Wild Edible Fungi and Blackberries (March 2000)


A survey on radioactivity levels in free foods collected from around four UK nuclear sites has been completed.1 Free foods are foods collected from the wild (not cultivated). Over forty samples of a range of foods were collected by members of the public over 1997 and 1998. Table 1 indicates which foods were collected from each site for analysis. The samples were analysed by a range of accredited methods for the following radionuclides: total tritium, tritiated water, organically bound tritium, carbon-14, sulphur-35, calcium-45, plutonium-239/240, americium-241 and total uranium. The range of radionuclides varied from site to site as indicated in Table 2. The objectives were: to find out the range of 'free foods' collected from around nuclear sites; to find out the quantities of food involved; and to assess how radiation doses (i.e. the quantity of radiation) received from eating these 'free foods' compared to doses from eating cultivated foods from around nuclear sites.

Over 80 different types of food were identified as being collected, some in significant quantities. On average 2.5 types of food were collected per person. Some people were noted to eat more than two foods at higher than average rates

Radiation doses from free-foods consumption are comparable to those from cultivated foods around the four nuclear sites studied. No annual dose was calculated to exceed six microsieverts. The legal limit for artificial (man-made) sources is 1000 microsieverts per annum. In comparison the national annual average from all natural sources is over 2000 microsieverts.


In England and Wales MAFF carries out surveillance programmes for radioactivity in the food chain. Most of the routine surveillance is targeted at foodstuffs produced in the vicinity of the major nuclear installations. This work allows MAFF to demonstrate that exposures from artificial sources of radioactivity are well within national limits and to estimate doses received by members of the public consuming food that is nationally available as well as that produced in the locality of nuclear installations.

The majority of food samples are collected from cultivated land, with a small proportion of samples being so-called 'free foods'. Free foods are those collected from the wild. In the past it was assumed that free foods did not make a significant contribution to the overall ingestion doses.

To test this assumption, as part of the Working Party on Radionuclides in Foods (WPRF) surveillance programme, a survey looked at the collection and consumption of free foods around four nuclear sites. Subsequent doses from the consumption of these foods were studied.


The four areas studied were around the Atomic Weapons Establishment (Aldermaston); Nycomed Amersham (Cardiff); Hinkley Point nuclear power station; and Sizewell nuclear power station.

A habit survey was conducted to identify people who make use of wild foodstuffs around these sites. Members of the British Market Research Bureau (BMRB) personally interviewed over 800 people. They were asked what types of food they collected, in what quantity and from where, and to mark the location on maps. They were also shown various sized containers and asked to estimate how many 'containers worth' they collected. In addition they were asked if they would be willing to collect foods for the project. Those who volunteered were asked to collect a selection of foods from their area. Sample selection was based on foods collected by the most people and in the largest quantities. Sampling was extended by a year due to a poor return from collectors. In the second year some samples were requested from two collectors to increase the chance of obtaining the required sample. In this way enough samples were obtained to give meaningful results.

All samples were analysed for gamma-emitting radionuclides. The other radionuclides selected for analysis were based on discharge data for each site and on radiological significance.


Between the 800 people interviewed over 80 different types of free food were identified as being collected. Blackberries were the most collected foods, but elderflowers and elderberries, as well as various types of mushroom and nuts, were also popular. Most people collected more than one type of free food, with the average being 2.5 types.

In contrast to cultivated foods the habit data suggest that some people do consume several free foods at higher than average rates, although generally the actual amounts are relatively low.

The results of estimates of doses from consumption of these free foods is given in Table 3. At average rates of consumption all were less than 2.9 microsieverts. At higher than average no sample exceeded six microsieverts.


The doses from free foods were comparable to those from cultivated foods. As such the National Radiological Protection Board recommended that comprehensive surveys of free foods were not warranted at present. However, for rigorous dose assessments free foods consumption may well need to be taken into consideration.

Dose estimates, even at higher than average consumption rates, were all below 6 microsieverts. These results are much lower than the national average of over 2000 microsieverts from natural sources


At each of the sites studied a substantial number of collectors of free foods could be readily identified. Over 80 different types of food were identified as being collected, some in significant quantities. On average they collected 2.5 types of food. Some people were noted to eat more than two foods at higher than average rates. No subsequent estimated doses were found to be significant, all being less than 0.3 per cent of the national average from natural sources.

A follow-up project has been commissioned looking at levels of natural radionuclides in free foods at locations remote from nuclear sites.

  1. Green, N., Hammond, D. J., Davidson, M. F., Wilkins, B. T., Richmond, S. and Brooker, S. (1999) Evaluation of the Radiological Impact of Free Foods found in the Vicinity of Nuclear Sites. Memorandum of the National Radiological Protection Board. NRPB-M1018.
Further Information

The full report of this study is held in the MAFF Library, Nobel House, 17 Smith Square, London, SW1P 3JR. Tel: + 44(0)20 7238 6575. If you would like to consult a copy, please contact the Library giving at least 24 hours notice or, alternatively, copies can be obtained from the Library; a charge will be made to cover photocopying and postage.

For further information please contact:

Mr P Tossell
MAFF, Joint Food Safety and Standards Group,
Radiological Safety and Nutrition Division,
Room 535 Ergon House,
c/o Nobel House,
17 Smith Square,

Tel: +44 (0)20 7238 6177
Fax: +44 (0)20 7238 6537
e-mail: p.tossell@fsci.maff.gov.uk

Units of Measurement

Microsieverts are units of radioactive dose.

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These pages were last updated on 30 June 1999


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