High-altitude winds were to the east at the time of detonation and carried the radioactive debris toward Rongelap Atoll. Utrok Atoll also received fallout from the Bravo test but at much lower air and ground-level concentrations than at Rongelap Atoll. Other atolls received Bravo fallout at levels below that of Utr_k.
Today, scientists in Lawrence Livermore's Marshall Islands Dose Assessment and Radioecology Program work to minimize exposure through ingestion and other pathways for the Marshallese now living on or wishing to return to their islands. The program continues research begun nearly 30 years ago to characterize radiological conditions on affected islands and develop strategies to minimize radiological exposure to a people who want to resettle. The program also supports Marshallese efforts to implement radiation protection programs for residents wishing to track their exposure to radionuclides from fallout contamination that still lingers on the islands.
Previous assessments showed that 137Cs accounts for about 98 percent of the total dose for returning resident at the various atolls. About 85 percent to 90 percent of the dose (depending on the atoll) is from consumption of locally grown foods such as coconut meat and fluid, copra meat and milk, Pandanus fruit and breadfruit. About 10 percent of the dose is due to external gamma radiation from 137Cs in the soil. Isotopes of strontium, plutonium and americium account for less than 5 percent of the estimated dose.
The research appears as the cover article in the journal, Health Physics.
|Contact: Anne Stark|
DOE/Lawrence Livermore National Laboratory