Seventh report on radioactivity surveillance using dry cloths

Monday 14 April 2003

Dry cloths are devices designed to capture windborne dusts. These include radioactive material discharged from nuclear sites either routinely or during accidents that might deposit on agricultural land, leading to accumulation by crops or livestock and subsequent public exposure through consumption of agricultural products.

Between 1968 and 1972, the then Ministry of Agriculture, Fisheries and Food (MAFF) installed 175 of these devices around the 18 nuclear sites in England and Wales. The dry cloth programme helped it meet its statutory responsibilities for authorising the disposal of radioactive wastes from nuclear sites, which passed to the Environment Agency (EA) in 1996. However, MAFF, and later the Food Standards Agency, continued the programme as a measure to protect the food chain.

The cloths were collected monthly and analysed for radioactivity. The programme was disrupted in 2001 due to the outbreak of Foot and Mouth Disease, which created a break in the long running series of results. It was decided to terminate the programme in the summer of 2001, particularly as the Agency did not have any statutory responsibilities that needed this programme and its results had been of relatively little value. All the dry cloth devices were decommissioned by March 2002.

The attached report, the seventh and last in the series, describes the operation and results of the programme during the period 1995 to 2001. During this period, there were five instances of statistically elevated radioactivity measured by the devices although none of these could be linked directly to known or suspected releases of activity from nuclear sites.

The report gives detailed statistical data for measurements made at each of the 175 monitoring stations located around the 18 English and Welsh nuclear sites that were under surveillance. For completeness, the report also includes data that was available electronically for the period 1987 to 1994. Earlier data is held in the form of paper records.

Radiation exposures to consumers from radioactive discharges incorporated into the food chain are evaluated in the Radioactivity in Food and the Environment (RIFE) series of annual reports published jointly by the Food Standards Agency and the Scottish Environment Protection Agency. In all cases, the exposures due to the consumption of terrestrial foodstuffs are well below the statutory United Kingdom annual exposure limit for members of the public.