Thirty-five years ago, on April 26, 1986, the worst nuclear accident in history took place: a reactor exploded at the Chornobyl nuclear power plant in Ukraine.
After the explosion, the reactor smoldered for another two weeks, releasing invisible but deadly radioactive gases north of the country along the European continent. As a result, millions of people were affected.
Even 35 years after the disaster, it remains unclear to what extent the catastrophe harmed people’s health.
In the latest research, scientists from the U.S. National Cancer Institute (NCI) looked into the effects of ionizing radiation on human health, including long-term, caused by the Chornobyl tragedy.
The NCI scientists used next-generation DNA tools to study biosamples of people in Ukraine affected by the Chornobyl explosion.
They conducted two studies.
The first one aimed to find out if children received any genetic changes from their irradiated parents, who were either workers who helped to clean up territory after the explosion or evacuated residents of the nearby town of Pripyat.
For this, scientists analyzed the genomes of 105 mother-father pairs and 130 people who were born between 1987 and 2002, to see if there was an increase in random genetic changes, known as de novo mutations.
Surprisingly, the results showed that ionizing radiation had minimal effect on such mutations.
According to the director of NCI’s Division of Cancer Epidemiology and Genetics Dr. Stephen Chanock, such results give hope for people who lived in Japan’s Fukushima, where a tsunami caused a nuclear accident in 2011.
“The radiation doses in Japan are known to have been lower than those recorded at Chornobyl,” said Chanock.
The second NCI study profiled genetic changes of 359 people who became sick with thyroid tumors as they were affected by radiation as a child, or when they were as embryos in their mothers’ wombs.
It showed that the risk of thyroid cancer was much higher as a result of the nuclear accident.
“The energy from ionizing radiation breaks the chemical bonds in DNA, resulting in a number of different types of damage,” the study reads.
According to Lindsay Morton, deputy chief of the Radiation Epidemiology Branch, the study became possible thanks to the Chernobyl Tissue Bank created over two decades ago, when genetic studies were extremely rare.
At that time, scientists collected tumor samples from people in highly contaminated regions with the hope that emerging technologies will provide more answers in the future.
“These studies represent the first time our group has done molecular studies using the biospecimens that were collected by our colleagues in Ukraine,” Morton said.
