ENVIRONMENTAL-IMPACT OF PARTICLES EMITTED FROM WINDSCALE PILES, 1954-7

During 1954-7 particles of irradiated uranium oxide were emitted from the Windscale Piles. The particles were large compared with most ambient aerosols, 85% by weight being between 10 and 100 mu m diameter, and they mostly fell within a few kilometers of the works. From measurements of activity in soil in 1958 onwards, it is estimated that about 12kg of uranium, 20 Ci of **1**3**7Cs, 18 Ci of **9**0Sr and 0. 3 Ci of **2**3**9** plus **2**4**0 Pu were emitted. To estimate the concentrations of **9**0Sr and **1**3**7Cs in milk during the emissions, comparison is made with the fallout of fission products from bomb tests, which also began in 1954, but continued longer. It is calculated that the average level of **9**0Sr in milk at Seascale, 1954-7, was 36 pCi per g Ca, with higher concentrations, 100-200 pCi (g Ca)** minus **1, in milk from farms immediately surrounding the Windscale plant. For comparison, in 1963/5 the average level of **9**0Sr in milk in the UK was 20-30 pCi (g Ca)** minus **1, with 90-170pCi (g Ca)** minus **1 in milk from certain hill farms.