The researchers recommend that people should not return to some of the Marshall Islands because radiation is still above safe threshold.

Some of the Marshall Islands in the Pacific Ocean, such as Bikini Atoll and Enewetak, are still more radioactive than Chernobyl and Fukushima, although more than 60 years have passed since the US tested nuclear weapons in the region. this. When testing plutonium-239 and 240 isotopes in soil samples, the researchers found that some islands are 10 to 1,000 times more radioactive than Fukushima and about 10 times the Chernobyl forbidden zone.

In 2016, a team at Columbia University in New York published a paper in the journal Proceedings of the National Academy of Sciences (PNAS) on background gamma radiation north of the Marshall Islands, including the islands of Enewetak, Bikini and Rongelap. . They found that the radioactivity on Bikini Island was higher than previously reported, so they decided to conduct further research on radioactivity on the islands.

On July 15, the research team published three new works in the PNAS journal about four Marshall Islands atolls: Bikini, Enewetak, Rongelap and Utirik. The amount of gamma radiation in Bikini Atoll, Enjebi Island on Enewetak Atoll and Naen Island on Rongelap Atoll is much higher than an island in the southern Marshall Islands that scientists refer to.

Mushroom cloud in Romeo nuclear bomb explosion on Bikini island. (Photo:

The amount of radioactivity on Bikini and Naen Islands was so high that it exceeded the maximum limit agreed by the United States and the Marshall Islands in the 1990s. The researchers also discovered Runit and Enjebi islands of Enewetak Atoll, as well as Bikini and Naen Island, have a high level of radioactivity in the soil.

In the second study, the scientists worked with professional divers to collect 130 acres of land from the Bravo Castle crater in Bikini Atoll. Some isotopes like plutonium-239 and -240, americium-241 and bismuth-207 are higher than others in the Marshall Islands.

In the third study, the authors examined more than 200 fruits, mainly coconuts and pineapples on 11 islands of 4 atolls north of the Marshall Islands. As a result, the amount of cesium-137 in many fruits on Bikini and Rongelap islands is well above the safe threshold.