|Fig. 1: The Fukushima Nuclear Power Plant prior to the explosion. (Source: Wikimedia Commons)|
On March 11, 2011 the Japanese Fukushima Daiichi nuclear power plant (seen in Fig. 1) was significantly damaged by a major earthquake and subsequent tsunami. Three reactors suffered explosions, and radioactive materials leaked out of the plant into the surrounding area. It marks only the second ever Level 7 nuclear disaster in history. Following this accident in 2011, there were 440 nuclear reactors in the world, and 4 of those had been the cause of some sort of radioactive release- Three Mile Island (1979), Saint-Laurent (1980), Chernobyl (1986), and Fukushima.  Each incident garnered international attention, and concern regarding radiation exposure continues to affect Japan as well as cautious scientists around the world. With 3 previous nuclear incidents having provided decades of data regarding radiation levels and their health effects, the question now is how concerned should Japan and the world be about the ongoing situation in Fukushima? How does this accident compare with previous accidents? It would seem the answer is somewhere in between the relatively inconsequential Three Mile Island and the meltdown in Chernobyl. It should be noted that there is little objective information available regarding the Fukushima plant since the explosions. much of the information available regarding the accident is based on political reports or expert opinions and projections.
In terms of sheer amount of radioactive material released and levels of exposure, Fukushima is fairly alarming. Approximately 9 × 1015 Bq of radioactive substances have been released since March 11, affecting around 1800 square kilometers of land in Japan with varying levels of radiation.  One Japanese researcher believes this to be equivalent to "29 Hiroshima-type atomic bombs".  An estimated 14,000 people were exposed to some amount of radiation within four months of the accident, and hospitals have reported treating ailments they attribute to that exposure. [2,3] This does not account for the workers entering the plant in the wake of the accident, nor those affected by acute radiation at the plant, only civilians.
In contrast, the radiation released from Three Mile Island was a small fraction of that released in Fukushima, which turned out to have negligible health effects even for people living within five miles of the plant.  However, Fukushima released only approximately 1/6 the amount of radiation from Chernobyl.  Another important note is that the Chernobyl plant is landlocked; radiation plumes spread to other nations and affected many more people, while several estimates believe that over 75% of the radiation released at Fukushima was averted over the Pacific Ocean, where it was diluted and its effects on civilians will be mitigated before reaching other countries. 
Paired with the fact that less radiation ended up on land is the knowledge gained following the Chernobyl accident. In 1986, many people in areas affected by the radiation were unaware of the risks involved with ingesting contaminated materials, and ended up unknowingly increasing their risk for cancer or even death. Thousands of deaths over the past few decades have been linked to radiation from Chernobyl. While it is still early to tell the real impact of Fukushima, citizens are aware of potential risks and more likely to avoid additional risky behavior now than almost 30 years ago. Although the Japanese government has been inexplicably idle regarding a response to the fallout of Fukushima and potential cleanup, scientists at institutions around the country have been conducting their own independent testing to ensure their own safety. 
Along with the physical dangers of exposure to radiation come psychological concerns. A major concern following the accidents in Three Mile Island as well as Chernobyl was the mental stress on people living near the plant, wondering if their health would be affected. While these people may not have been adversely affected by the radiation, the stress of the unknown caused depression, anxiety, and other disorders.  Furthermore, Japanese citizens are developing distrust for their idle government regarding the Fukushima accident. Distrust combined with stress could be a potential recipe for political turmoil.
Based on data collected and projections of the Fukushima incident, it would appear that there is minor cause for concern. There will likely be little international impact, and the number of people affected dangerously by radiation is relatively small. Still, deposits of radiation into the ocean and other hotspots, if not decontaminated, could have adverse effects for years to come. It is still early to tell, but it is unlikely that the accident in Fukushima will be another Chernobyl. One would hope that the Japanese government finally takes a proactive approach in radiation cleanup and safety of its citizens.
© Austin Barr. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 J. E. Ten Hoeve and M. Z. Jacobson, "Worldwide Health Effects of the Fukushima Daiichi Nuclear Accident," Energy Environ. Sci. 5, 8758 (2012).
 K. Kurokawa et al., "The Offical Report of the Fukushima Nuclear Accident Independent Investigation Commission: Executive Summary," National Diet of Japan, 2012.
 D. Jamail, "Fukushima Radiation Alarms Doctors," Al Jazeera, 18 Aug 11.
 J. G. Kemeny et al., "Report of the President's Commission on the Accident at Three Mile Island," Office of the President, October 1979.