13705 AND Sr RETENTION FROM RONGELAP FOODS
755
The net absorption (intake—fecal excretion expressed as percent of
intake) was 30%, a factor of 2 higher than the average for 10 normal
adults on a high-calcium diet reported by Spencer et al.*! The low
fecal calcium excretion found in the present study wasindicative of a
high "sr absorption.
Although the retention curve for "Sr shows that the biological
half-life varies with time after exposure, the data do not fit a power
function as found by others.'*?° If it had been possible to measure
excreta over a longer period of time, a power function may have been
described.
SUMMARY
The ‘cs and the Sr body burdens of people living on Rongelap
Island are high compared to most other populations of the world. The
reason for this is that the natives consume foods that are contaminated
with long-lived fission-product radioactivity resulting from a fallout
incursion in 1954. Their '"Cs body burdens are comparable to those of
people living in other limited areas such as Lapland and northern
Alaska where unique ecological conditions are conducive to high lcs
concentrations in indigenous foods. The metabolism of ‘Cs and "Sr
has
been studied in the Lapland and Alaskan groups but not in the
Rongelap natives.
Since facilities for a metabolic-balance study were not available
on Rongelap Island,
several native food items were brought back to
BNL and consumed by one of the authors under controlled conditions.
Urinary and fecal specimens were collected and whole-body counting
measurements were made over a period of 180 days. The intake of Sr
over a seven-day period was 20 times higher than normal andthat of
137Cs was 60 times higher than normal.
Fifty percent of the ingested '’Cs in the Rongelap food had been
excreted in urine after 85 days, whereas 14% had been eliminated in
feces during the same time. In contrast, most of the “Sr was un-
absorbed. Fifty percent had been excreted in feces at 10 days, whereas
only 244% had been excreted in urine. The retention of '’Cs as de-
termined by both whole-body counting and excretion measurements
showed a biological half-life of 74 days. Strontium-90 retention as a
function of time was best described as a series of exponentials and
approached a value of 25% after 140 days.
These findings fall within the range of results of many other
studies conducted under a wide variety of natural, accidental, and
experimental conditions.
ACKNOWLEDGMENTS
The authors are grateful to John Ankain of Rongelap Island for
collecting and preparing the native foods. We wish to thank Stanton