Larger amounts of radioactive xenon isotopes were emitted from Fukushima than Chornobyl because the accident at Fukushima involved three reactors rather than the one at Chornobyl. These isotopes are noble gases with short half-lives: the longest, xenon-133, has a half-life of 5.2 days.
The February 2013 World Health Organization (WHO) report on Fukushima mentioned that, among those living near Fukushima, there was a 6 percent higher risk of breast cancer in females exposed as infants and a 7 percent higher risk of leukemia in males. These could be underestimates as there were large uncertainties in estimated doses. The report also stated there was a 70 percent higher risk of thyroid cancer in women exposed as infants. Unfortunately, the report was often vague, claiming that health risks for the general population in Japan were “low.” It also claimed that there was no discernible increase in health risks expected outside Japan and that one-third of emergency workers at Fukushima Daiichi were expected to have increased risks.
The effects observed after Chornobyl indicate what lies ahead at Fukushima. After about nine months, we can expect the teratogenic, or in utero, effects of radiation exposure, including infant deaths, infant leukemias, and a decline in birth numbers. After two years, we can expect increases in the incidence of leukemia in adults, although this would be hard to detect as leukemia is a relatively rare disease. After four years, we can expect increases in thyroid cancers among women and children. After ten years, there will be increases in the incidence of solid cancers and cardiovascular effects.
Dr. Alfred Körblein, from Nuremberg, Germany, found peaks in infant mortality about six weeks after March 11, 2011. He showed a statistically significant threefold increase in the infant mortality rate: an observed rate of nine per thousand compared to the background rate of three per thousand. This increased infant death rate was clearly anomalous. Nine months later, he observed a 15 percent reduction in live birth numbers in Fukushima Prefecture and a 5 percent reduction in all of Japan, which were also statistically significant. This was similar to what occurred in the city of Kiev nine months after Chornobyl.
Adult leukemia from Chornobyl exposures was difficult to detect because any increases were small compared to existing levels. However, in 2012, Dr. Lydia Zablotska studied over 110,000 Chornobyl liquidators exposed to high levels of radioactivity. She found clear evidence of increases in leukemia, and the results were statistically significant because of the large number of people studied. Also of significance was their finding of a linear dose response down to 115 millisieverts.
In four or five years, there will probably be increases in the incidence of thyroid cancer, although perhaps not to the degree that occurred after Chornobyl. There the affected populations before the accident had iodine deficiencies in their thyroids as they lived thousands of miles from the sea and did not have much seafood in their diets. In Japan, all people live near the sea and most have diets rich in seafood, so their thyroids are stacked up with stable iodine. However, there have already been increases in the number of small cysts and nodules found in children’s thyroids in Fukushima, although it remains unclear how many of these will develop into cancers. Thyroid cancers only appeared in children at Chornobyl four years after the accident.
Based on what is known about fallout exposures, estimates can be made of average doses to people and the numbers who will die from cancer from the accident. Once the collective dose to the population is identified, the anticipated number of fatal cancers can be estimated by multiplying the collective dose by the current accepted risk factor of 10 percent per sievert. There have been three studies in this area so far: by the French Institute de Radioprotection et de Sûreté Nucléaire (2011); by Ten Hoeve and Jacobsen (2012) in the United States; and by Beyea, Lyman, and Von Hippel (2013) in the United States. The French study estimated 1,000 to 1,500 deaths, Ten Hoeve and Jacobson 170, and Beyea, Lyman, and Von Hippel about 700. My own study from groundshine (the cesium left on the ground) estimates about 3,000 deaths over the next seventy years, which is how long the cesium will last.
A professor at Hirata Central Hospital studied whole-body counts from internal radiation of 32,000 people who entered his hospital between October 2011 and November 2012. He found a decline in the numbers of people testing positive for internal cesium—from 12 percent in 2011 to 3 percent in 2012. Safecast also has evidence that external radiation levels are declining, albeit slowly. These data are not from TEPCO but from citizen scientists performing their own measurements. These results are slightly encouraging, but clearly tens of thousands of Japanese people, especially in highly contaminated areas, will continue to receive relatively high radiation doses for many decades to come, as is still happening at Chornobyl.
The lesson we should take from Fukushima and Chornobyl is that governments that do not learn from history are condemned to repeat it.
9
The Biological Consequences of Chornobyl and Fukushima
Timothy Mousseau
A number of years ago, prior to March 11, 2011, my colleagues and I worked on the impact of radioactive contaminants in Chornobyl. Our interest was driven by evolutionary ecology and genetics, not radioecology, nor nuclear medicine, nor antinuclear activism. At first, we worked primarily with birds because they were easy to catch, identify, and count. Not discouraged by the fence around Chornobyl, birds entered the most contaminated areas of the site, and tracking them has allowed us to study the long-term health impact of these contaminants.
We have studied biodiversity at Chornobyl since 2000 and Fukushima since 2011. Most organisms that we have examined showed significantly increased rates of genetic damage in direct proportion to the level of exposure to radioactive contaminants. Many organisms showed increased rates of deformities, developmental abnormalities, eye cataracts, and even tumors and cancers. Reduced fertility rates were also common. We found that about 40 percent of male birds in the more contaminated parts of Chornobyl are completely sterile, with no sperm or only a few dead sperm. Many of the birds have reduced life spans. As a consequence, many of these populations are small and have reduced growth rates. Some of these species have actually died out in the most contaminated areas. Individuals of species that are surviving well now may accumulate mutations that will be passed on to the next generation. Some of these individuals live long enough to migrate out of the area, carrying these mutations and their potential effects to populations that have never been exposed to radiation.
Understanding the effects of radioactivity in the environment is not easy. All of us are different. Some of this is the result of genetic mutations that, even if they are expressed (most are not), probably do not influence our survival or ability to reproduce. The natural world is a complicated heterogeneous place. Every point in space and time is slightly different, for instance, with respect to the amount of sunlight it receives, the temperature, the plants and animals that are there, the birds that might fly by. In order to ascertain the effect of radioactivity or radioactive contaminants on an individual, a population, or a species, this variability must be factored into the equation. We have accomplished this by employing a massively replicated biotic inventory design, which involves counting every last organism in hundreds of places in both Chornobyl and Fukushima repeatedly through time.
At Fukushima, as of July 2012, we had made 700 biotic inventories. At Chornobyl, we stopped at 896. We measured the number of birds, the species of birds, the number of spiders, and so forth. We measured many of the environmental variables that might be relevant in determining the presence or absence of a given group of organisms—the meteorology, the hydrology, the species of plants, the presence of water. We set up about half a kilometer of mist nets to catch thousands of birds to obtain blood and feather samples for analysis of their DNA and their overall health. We measured radiation levels, too, first using a very simple measure of radiation levels—the Geiger counter. We then calculated the partial effects of radioactive contaminants on populations while statistically controlling for the many other environmental factors that can influence abundance and diversity. Such an approach had not ever been previously taken by any team of scientists.