Chernobyl

On April 26, 1986, unit 4 of the Chernobyl nuclear power plant in northern Ukraine exploded, giving rise to the worst nuclear disaster in history. A 200 ton metal plate that sealed the top of the reactor was blown off and hundreds of tons of graphite were ignited, which burned for ten days. It is still unknown how much radiation was released in the explosion and ensuing fire. A minimum estimate is around 100 million curies, equivalent to a medium size nuclear strike.

Radioactive particles were blown north and east, raining dangerous levels of radiation over thousands of square kilometers. Even regions as far away as Germany and Norway were affected. Increases in radiation have even been measures in Japan and the U.S.

Radiation and DNA Damage

Several people, to be precise 31, including firefighters died immediately after the accident as a result of radiation sickness. Of the 400,000 workers that buried radioactive waste and entombed whatever was left of the reactor, most are now ill, experiencing a variety of health issues, from reproductive disorders to immune suppression.

Radiation is a known mutagen, causing changes in DNA. Over ten thousand children in the area were exposed to levels of the radioactive isotope iodine-131, that were over 400 times the maximum allowed amount. This has consequences even to this day, as children in the Ukraine are over 10 time more likely to develop thyroid cancer than during the pre-Chernobyl times. In the cells of many people who lived near Chernobyl during the accident, chromosome mutations have been detected., and birth defects in the population have risen significantly.

Germ-Line Mutations

Research has been done on possible germ-line mutations (mutations passed on to future generations) by collecting and analyzing blood samples from several families who resided near the site of the nuclear power plant. These samples included children born after the incident.

Through DNA sequencing, germ-line mutations were identified and compared to a control group in Britain. The germ-line mutation rate was over twice as high in the Chernobyl group as in the control group.

Furthermore, even a correlation between the mutation rate and the surface radiation exposure was found: individuals living in areas that were exposed to higher levels of radiation, possessed a higher mutation rate than the people from less contaminated regions.

These findings illustrate clearly that radiation is one of the sources of mutations, which could potentially lead to serious DNA damage that can even be passed on through future generations.