This Island Is Still Very Radioactive Five Decades After Atomic Bomb Tests

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Bikini Island, in the central Pacific, was the site of 23 nuclear bomb tests in the middle of the last century. Unsurprisingly, the place is radioactive, and a study has found radiation levels far exceed expectations. However, Central Park is more radioactive than some of the islands near Bikini that were affected by the fallout from the tests.

Scientists from Columbia University measured gamma radiation at six islands in the Marshall Islands, including Bikini. It has now been 58 years since the last atomic bomb was tested there. Radiation was anticipated to come primarily from Cesium-137 produced in the bombs, which has a half-life of thirty years, so it should now be a quarter of what it was when testing stopped.

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In Proceedings of the National Academy of Sciences, the authors confirm that 90 percent of the radiation at Bikini comes from the decay of Cesium-137 to Barium-173, identifiable by the release of a 0.662 mega electron volt gamma ray.

With radiation dominated by a single source, calculations based on historical measures and decay rates ought to predict the situation today, but at Bikini Island, these predictions proved overly optimistic.

Encouragingly, radiation is low at Enewetak, home to almost all the six islands’ current population, averaging 7.6 millirems per year, well below accepted safety standards. Nevertheless, one disturbingly high measurement was made at Enewetak’s southern tip.

On Bikini Island, however, the average was 184 millirems per year, and one measurement was more than three times this. Bikini’s interior is far more radioactive than its coast. On its own, even 184 millirems per year is well below average American exposure, but could be multiplied to dangerous levels by eating local fish or fruit.

Bikini Island, in the central Pacific, was the site of 23 nuclear bomb tests in the middle of the last century. Unsurprisingly, the place is radioactive, and a study has found radiation levels far exceed expectations. However, Central Park is more radioactive than some of the islands near Bikini that were affected by the fallout from the tests.

Sikorsky_SH-3G_Sea_King_from_Helicopter_Combat_Support_Squadron_1_in_flight_during_an_aerial_radiation_survey_over_Bikini_Atoll_in_November_1978

Scientists from Columbia University measured gamma radiation at six islands in the Marshall Islands, including Bikini. It has now been 58 years since the last atomic bomb was tested there. Radiation was anticipated to come primarily from Cesium-137 produced in the bombs, which has a half-life of thirty years, so it should now be a quarter of what it was when testing stopped.

In Proceedings of the National Academy of Sciences, the authors confirm that 90 percent of the radiation at Bikini comes from the decay of Cesium-137 to Barium-173, identifiable by the release of a 0.662 mega electron volt gamma ray.

With radiation dominated by a single source, calculations based on historical measures and decay rates ought to predict the situation today, but at Bikini Island, these predictions proved overly optimistic.

Encouragingly, radiation is low at Enewetak, home to almost all the six islands’ current population, averaging 7.6 millirems per year, well below accepted safety standards. Nevertheless, one disturbingly high measurement was made at Enewetak’s southern tip.

On Bikini Island, however, the average was 184 millirems per year, and one measurement was more than three times this. Bikini’s interior is far more radioactive than its coast. On its own, even 184 millirems per year is well below average American exposure, but could be multiplied to dangerous levels by eating local fish or fruit.

Source:

iflscience.com



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