THE DEPOSITION OF STRONTIUM 89 AND STRONTIUM 90 ON AGRICULTURAL LAND AND THEIR ENTRY INTO MILK AFTER THE REACTOR ACCIDENT AT WINDSCALE IN OCTOBER 1957

摘要

On farms within two miles of Windscale Works, the deposition of strontium 90 was on average 160 mμc per square metre. The value fell off rapidly with distance from Pile No.1. The maximum value, 678 mμc per square metre, was observed in a field adjoining the Works and owned by the Authority. The value expected from fall-out from weapon tests would have been between about 10 and 15 mμc per square metre. The mean strontium 90 content in milk from the farm which showed the highest levels was 7 per cent of the maximum permissible level now recommended for such conditions by the Medical Research Council.nOn the farms studied at greater distances from the Works, fall-out from weapon tests was the major source of the strontium 90 on agricultural land. The evidence suggests that some strontium 90 emitted from the factory was present, but it was insufficient to be distinguished unequivocally from world-wide fall-out. There is no evidence that strontium 90 released from the Works entered milk produced in this region to an appreciable extent during 1958;a comparison of the ratios of strontium 89 to strontium 90 in milk with that in the material emitted from the Works and in current fall-out shows that the contamination of milk was predominantly, if not entirely, due to recent fall-out from weapon tests.