We still don’t really know the health hazards of a nuclear accident

severe Chernobyl accident, radioactive elements including iodine-131 and cesium-137 were spread by graphite fires across a wide area. People in the vicinity of the fires (mainly firefighters) were exposed to fatal doses of radiation (300,000 mSv per hour). Nearly a third of them died in the months following the accidents.

But for people who have lived in the most contaminated areas of Belarus, the Russian Federation and Ukraine at some point since the accident it is more difficult to estimate the impact. They have received relatively low doses of radiation over a long time, estimated as 1 mSv per year on average. While there was an initial spike in thyroid cancer cases, it is difficult to work out whether other cancers in this population are due to radiation or other lifestyle factors.

So is Chernobyl now safe? If you take a tour of it today, expect radiation doses of 0.2 to 20 mSv per hour depending on how close to the reactor you go. The levels of radioactivity from radioactive cesium and strontium have already dropped by half – and in 30 years time they will half again. After ten “half-lives” (300 years) the radioactivity would decayed to normal background levels.

Relocation versus radiation
But the effect of radiation is not everything. More than 116,000 people from the area surrounding Chernobyl were evacuated but about 1,200 refused. These so-called “Babushkas of Chernobyl,” all over 40 at the time of the accident, defiantly ignored the law and decided to take their chances against the radiation rather than being displaced from their beloved homes and communities. More than 200 of these remain living in the area today.

And perhaps they were right to stay — the World Health Organization (WHO) cites relocation from Chernobyl as a cause of stress, anxiety, mental illness and “medically unexplained physical symptoms”. To this day, we do not know the true cost of relocation on lives because it was not formally measured.

The radioactive fallout at Fukushima was less than 10 percent of that at Chernobyl. A number of scientists have suggested the evacuation was therefore too cautious. Others recommend that the acceptable radiation dose to the public set by international organizations is too conservative and could be significantly increased without causing harm.

There seems to be little evidence to suggest that lower doses of radiation causes a big risk. It has even been suggested that the body may have some sort of cellular repair mechanisms to deal with lower doses. The problem is we simply just don’t know for sure – the only way to find out is to study the people who have been exposed to these low doses over their entire lives, an enormous task that not everyone is willing to take part in.

The people of Fukushima, except those in the worst contaminated areas, will eventually be encouraged to return to their homes. In the absence of better understanding, scientific and political arguments about how safe the radiation levels are will continue. What is abundantly clear, though, is that we need to understand the comparative health effects of radiation versus relocation. Developing a new approach in our response to nuclear accidents and the decisions that are made in their immediate aftermath is vital so that we can avoid unnecessary panic and evacuation — something virtually all scientists agree on.

Claire Corkhill is Research Fellow in nuclear waste disposal, University of Sheffield. This article is published courtesy of The Conversation (under Creative Commons-Attribution/No derivative).