Following the Fukushima accident in March 2011, grass samples were collected from 42 sites around Great Britain during April 2011. Iodine-131 was measurable in grass samples across the country with activity concentrations ranging from 10 to 55 Bq per kg dry matter. Concentrations were similar to those reported in other European countries. Rainwater and some foodstuffs were also analysed from a limited number of sites. Of these, I-131 was only detectable in sheep's milk (c. 2 Bq/kg). Caesium-134, which can be attributed to releases from the Fukushima reactors, was detectable in six of the grass samples (4-8 Bq/kg dry matter); 137Cs was detected in a larger number of grass samples although previous release sources (atmospheric weapons test and the 1986 Chernobyl and 1957 Windscale accidents) are likely to have contributed to this. All data and information for this sampling are available from this record. The data result from collaboration between CEH and the University of Stirling.
Publication date: 2011-12-31
Fresh grass and other vegetation samples were finely chopped and accurately weighed into 950 ml plastic containers prior to gamma analyses. Milk (sheep and goat), rainwater and homogenised egg content samples were accurately weighed into either 150 ml or 950 ml plastic containers depending upon the sample volume available. To determine the activity concentration of gamma-emitting radionuclides, fresh samples were analysed on hyper-pure germanium detectors as soon as possible after sampling and counted for 1-2 days depending upon their 131I activity concentration. The detectors are calibrated against standards of various density and volume, and the facilities regularly participate in proficiency testing schemes.