Behavior of radiostrontium in rain and air after the ninth Chinese Atmospheric Nuclear Test

Strontium 89 and 90 were measured in rain water and air at Fayetteville, Arkansas (36°N, 94°W), for 9 months after the ninth Chinese atmospheric nuclear test. The 89Sr/90Sr activity ratios showed behavior very similar to the pattern of variation observed after the eighth Chinese atmospheric test. Ratios of 89Sr or 90Sr activity in rains to activity in air samples were computed, and these scavenging ratios were found to vary widely, but those for 89Sr tended to be higher than those for 90Sr. These ratios did not have a well-defined relationship with time, amount of rainfall, or a number of meteorological parameters. The data, however, indicate that a consistent relationship between fallout and rainfall may be necessary for scavenging ratios to be meaningful and useful on a short-term basis. This relationship apparently does not exist in areas of high cumulative deposition of 90Sr, such as Fayetteville.