Scientists find out how residual radiation affects Chernobyl frogs

They found that the level of radiation these amphibians were exposed to did not accelerate their aging or increase their levels of the stress hormone corticosterone.

Progress of the study

From 2016 to 2018, the scientists studied eastern quakes (Hyla orientalis) in the exclusion zone of the Chernobyl nuclear power plant. They collected more than 200 male frogs from 14 different sites with varying levels of radioactive contamination, from the most contaminated to completely clean sites.

Each frog was examined for accumulated radiation by measuring caesium in the muscles and strontium in the bones. This provided one of the most accurate estimates of radiation absorbed by vertebrate animals at Chernobyl.

Key findings

• Age and aging rate: The scientists determined the age of the frogs by the annual growth lines in their bones, similar to determining the age of trees by their rings. They also measured the length of telomeres, the end sections of chromosomes that shorten with each cell division. The results showed that neither the age nor the rate of aging of the frogs was affected by the level of radiation in their habitat.

• Stress hormone levels: Analysis of corticosterone levels in the blood of amphibians showed no significant differences between individuals from contaminated and clean areas.

Significance of the study

Zoology professor Herman Orisaola said that the current radiation levels at Chernobyl are not sufficient to cause chronic harm to the frogs. This is an important finding that helps to properly assess the current environmental impact of the accident.

The results reinforce the idea that the Chernobyl Exclusion Zone has become a kind of wildlife sanctuary that needs to be preserved. Although almost four decades have passed since the disaster and radiation levels have decreased significantly (less than 10% of the original radiation remains), it is important to continue monitoring and research.