The global strontium 90 budget

Inventories of Sr90 in the earth's environment have been made for a series of dates between August 1961 and March 1965. On every date tested these inventories are found to be deficient when compared with the amount of Sr90 expected to be present, on the basis of nuclear weapons tests conducted in the atmosphere. The major portion of this deficiency is attributed to a 33% error in the inventory of Sr90 deposited on the earth's surface that is caused by assuming that the observed fallout on land is equivalent to that on the oceans, per unit area. It is suggested that water bodies collect fallout 1.5 times more efficiently than land. Applying this factor to the worldwide Sr90 deposition inventory results in good agreement between stratospheric depletion and worldwide deposition, in addition to accounting for the apparent budget deficiency.