131I in the thyroid glands of sheep from Wales and south-west England after the Chernobyl accident.

Radioactive material from the Chernobyl reactor was deposited over the United Kingdom between May 2 and May 4, 1986. In this report, the 131I content of ovine thyroid glands, collected from seven abattoirs in Wales and south-west England is used to monitor the geographical distribution of the contamination. The results indicate that there was considerable local variation in the degree of contamination and suggest that, in addition to the major areas of contamination, deposition of high levels of radioactive material also occurred in isolated areas in the south-west of England. These observations confirm the value of monitoring 131I in the thyroid glands of grazing ruminants as a sensitive index of environmental contamination with the products of nuclear fission.