Radioactive clouds at the Bikini Atoll on May 21, 1956. Photo / AP
Radioactive clouds at the Bikini Atoll on May 21, 1956. Photo / AP
Radioactivity can still be found in the soil and food decades after the US ended nuclear testing in the Marshall Islands, with the highest levels found at the infamous Bikini Atoll.
Three new papers, published in the noted journal PNAS (Proceedings of the National Academy of Sciences of the United States of America), show that gamma radiation can still be found even more than half a century since testing in the region ended.
One of the studies showed that fruits, including coconuts, grown in some of the northern Marshall Islands are contaminated with a radioactive isotope of caesium at much higher levels than those found near Chernobyl or Fukushima.
Radioactive isotopes have been found in coconuts grown in the northern Marshall Islands. Photo / File
Dr David Krofchek from the University of Auckland said the three papers are the "first large scale measurements of radioactive isotopes produced from the US testing of nuclear weapons from 1946 through 1958 in the Marshall Islands".
"Foods tested, coconuts and pandanus, show a variety of radioactivity levels with the lowest levels detected in fruits from atolls farthest away from the weapons test sites. Northern atolls where most weapons tests were performed showed the much higher radioactivity levels. Bikini Atoll had considerably larger levels, well above most international norms for food safety. Research needs to be done on local sea food."
Krofchek added: "Both Bikini and Naen atolls also had the highest soil radiation, mostly from gamma rays, than any of the southern atolls. Bikini, which maintained the highest population before 1946, is certainly too contaminated to consider for population relocation."
The resident population of Bikini was relocated in 1946 before the US began the nuclear testing where 23 devices were tested across seven sites.
An attempt was made by some of the residents to return in 1972, after US testing showed that radiation levels were safe.
After the population started to suffer health effects such as miscarriage and stillbirth the residents were moved again, later claiming compensation from the US government.
Bikini residents are relocated before testing begins. Photo / AP
Cris Ardouin and Michael Lechermann, senior scientists from NZ's National Radiation Laboratory said that "fallout from nuclear weapons testing has entered the Earth's environment on a global scale".
It is known that former test sites like the ones on the Marshall Islands show elevated levels of radioactivity. The exposure to radiation associated with environmental radioactivity at the reported levels is generally low or comparable to other sources of radiation, such as naturally occurring radon, cosmic radiation at higher altitudes and diagnostic medical exposures."
They added that "the National Radiation Laboratory, now within ESR, has been continuously monitoring environmental radioactivity in New Zealand and the South Pacific region since 1960. Levels of radioactive fallout have continued to decline as would be expected since the cessation of nuclear weapons testing in the region".
The British also tested nuclear weapons in the Pacific, exploding devices in Kiribati, while the French tested in French Polynesia right up until 1995, a year before the Comprehensive Test Ban Treaty was signed.
