Page 5: The United States’ Nuclear Testing Programme

From 1946 to 1958, the Bikini Atoll–a Micronesian, volcanic island group in the Pacific Ocean (part of the Marshall Islands)–was “home” to 23, U.S.-conducted, nuclear detonations, including the first true Hydrogen bomb test, in 1954.

Environmental impacts

According to the U.S. Centers for Disease Control and Prevention, the tests in the Marshall Islands released 6.3 billion curies (See Chart 2) of I-131 alone, which is 42 times the amount released by atmospheric nuclear testing in Nevada.

After the Bravo test, the soil and water at Bikini atoll contained radioactive isotopes of caesium, cobalt, strontium, americium, and plutonium (see Chart 1). In Radioactivity and Rights Clashes at Bikini Atoll, Ruth Levy Guyer describes how the radioactivity in the lagoon and sea eventually disappeared as a result of slow and steady dilution in the ocean. The radioactivity, however, has remained on the islands. Coconuts on Bikini are still radioactive because coconut palm trees absorb caesium-137 and other radioactive elements from the soil. These elements are then concentrated in the fruit.

Islanders evacuated again

In 1972, more than 100 people moved back to Bikini after the United States declared the island to be “radiologically safe”. Laboratory tests in 1978, however, indicated that the returnees’ had ingested unacceptably high levels of caesium-137 and strontium-90, and they were again evacuated from the island.

Coconuts on Bikini are still radioactive because coconut palm trees absorb caesium 137 and other radioactive elements from the soil. These elements are then concentrated in the fruit.
"A Marshallese woman with her child, whom she believes was born with deformities caused by radioactive fallout." Photograph by Dennis O'Rourke © Copyright Camerawork Pty Ltd.

IAEA report confirms previously recorded values

In response to a request by the Government of the Marshall Islands to conduct an independent review of the radiological conditions at Bikini atoll, the International Atomic Energy Agency (IAEA) sent an environmental monitoring team there in May 1997. The team performed a limited programme of environmental measurements and sampling. Measurements were made of the absorbed dose rate in the air and of the concentration of the most radiologically significant radionuclides in samples of soil and foodstuffs. Measurements taken during the survey generally validated the data that had been collected previously. The IAEA review recommended that “Bikini Island should not be permanently resettled under the present radiological conditions. This recommendation was based on the assumption that persons resettling on the island would consume a diet of entirely locally produced food. The radiological data support that if a diet of this type were permitted, it could lead to an annual effective dose of about 15 mSv. This level was judged to require intervention of some type for radiation protection purposes.”