Interhemispheric transport of atmospheric fission debris from French nuclear tests

Radioactive iodine-131 (half-life, 8.06 days) and barium-140 (half-life, 12.8 days), released into the atmosphere (21 degrees S, 137 degrees W) by the French nuclear tests conducted during the period 24 August to 8 September 1968, have been observed in rainfall at Arkadelphia, Arkansas (34 degrees N, 94 degrees W). The maximum time required for the transport of the debris from a mid-southern to a mid-northern latitude appears to be about 3 weeks.