Tortoise and turtle shells can be used to study nuclear pollution. scientists have found. Just as tree rings can provide snapshots (简要说明) of the Earth's climate, and ice cores can give us information on past temperature, researchers found that the layers of shells can be used as a time stamp of periods with nuclear fallout.
The researchers focused on turtles and tortoises from areas that have seen nuclear pollution. and measured the uranium (铀) that was present in the bony outer shell that is usually made of keratin (角蛋白) . Each layer of shell equals to one year of the tortoise's life, and so can reveal what happened in its surrounding environment.
Five different turtles and tortoises from natural history collections were studied. One of these came from Enewetak Atoll, and was collected in 1978. Enewetak Atoll and its neighbour, Bikini Atoll, in the Pacific, were the sites of 67 nuclear tests, with Enewetak the site of 43 of these. Though the sea turtle was probably not alive during the time of the testing, researchers still found uranium pollution in the turtle 20 years after testing ended.
Researchers also looked at an eastern box turtle from Oak Ridge, Tennessee, in the US. Oak Ridge is the site of a nuclear facility that has produced and processed uranium since 1943. The turtle that was studied from there was collected in 1962 and may have bioaccumulated radionuclides, or radioactive materials, from uranium waste products in the area.
The research supports the idea that these animals can bioaccumulate human-made radionuclides, or from the environment. It also supports the idea that these animals. Which often live a long time, can record information about human activity with nuclear landscapes over a long period. We anticipate that combining analyses of historically collected and modern samples will significantly expand our environmental monitoring abilities as they relate to ongoing nuclear pollution questions.
