The cantankerous effects from Japan’s radiation
Devra Davis, PhD, MPH, president of Environmental Health Trust, is an award-winning scientist and writer on environmental health issues, author of “The Secret History of the War on Cancer,” and “Disconnect” who served as the founding director of the Board on Environmental Studies and Toxicology at the U.S. National Academy of Sciences, 1983-93. The opinions expressed are her own.
The discovery of ionizing radiation at the turn of the nineteenth century revolutionized science and society. Within two weeks of their being created at the end of 1895, the stunning x-ray images of his wife’s bejeweled hand that physics professor Wilhelm Conrad Röntgen had taken appeared in major newspapers around the world. From Paris, to London and Tokyo, scientists and celebrities engaged in a world-wide medical vogue with fashionable x-ray parties featuring popular demonstrations of moving skeletons.
This extraordinary discovery in fact came with extraordinary risks. The same technology that could light up lurking solid tumors of the lung and stomach and save lives on the battle field also damaged the ability of bone to make healthy red blood cells and induced an array of crippling deformities. Girls who worked hand-painting clock dials with luminescent radioactive paint and wet their brushes with their tongues to craft fine lines lost their jawbones years later. Men who chipped uranium out of the earth eventually grew pale as their blood became swamped with white blood cells and bereft of iron by aplastic anemia and leukemia.
These deadly problems were believed to arise only decades after high doses of radiation exposure had taken place. At the time that Enrico Fermi and Leo Szilard split the atom in 1934 to produce nuclear energy, many hoped that the dangers of radiation resided solely with massive releases that added up over the long term–the sort that sickened Nobel Laureate Marie Curie and made her notebooks too hot to handle. Donald Hornig, the man who literally sat upon the atom bomb as he developed the wiring for the trigger, once told me that “We all figured we were young, healthy and smart. So long as we didn’t do anything stupid to set things off, we would be fine.”
One of the first irrefutable signs that general population exposures to lower levels of ionizing radiation were not fine occurred two decades after the bombs that ended World War Two, when increased rates of cancers were found in Japanese survivors. Others reported that women exposed to unfocused radiation from fluoroscopic x-ray exams carried out for tuberculosis screening after the war ended had increased risks of breast cancer three decades later and that children treated for ringworm with radiation to their heads had increased brain tumors.
Nuclear power plants have been touted as safe, because their releases of radiation are believed to be so slight. We have also assumed that their spent fuel remains spent, out of sight and out of harm’s way. The Chernobyl nuclear plant containment meltdown in 1986 released radiation comparable to several hundred Hiroshima bombs into the environment and marked the beginning of the end of the secret Soviet system. This tragic natural experiment made several important additions to the literature. Less than a decade after the meltdown of this uncontained Soviet reactor, children, who normally do not develop thyroid cancer at all, had unusual patterns of the disease.
The citizens of Sweden were given potassium iodide to avoid uptake of radioactive iodine-131 and block the development of radiogenic thyroid cancer, but those in others nations—including many from nearby Ukraine– were not so lucky.
Chernobyl impacts were not just local. Increases in low birth weight babies and in those born with smaller brains and mental retardation occurred in some of the populations downwind of Chernobyl — a finding that did not make headlines and did not surprise those who understand why pregnant women should not routinely be given prenatal x-rays.
A newly published analysis by leading Russian scientists for the New York Academy of Sciences confirms that birds from the contaminated zones also had smaller brains and more skeletal defects.
While many factors are at play, four times more children from surrounding areas were deemed unhealthy in the decades following this nuclear plant meltdown. Cohorts that emigrated to Israel from Kiev have been followed and found to have increased tumor patterns tied with this explosive release some two decades later.
In coming to terms with the nuclear radiation genie, society has accepted some risks, but those now facing the citizens of Tokyo are beyond what anyone would have imagined possible. Nuclear-powered energy appears to be one of the greenest forms of energy in the world, because it releases no carbon-containing greenhouse gases when working. But, there are major unresolved issues that the unfolding Japanese dilemma make clear.
Certainly the workers fighting to keep the Fukushima Dai-ichi plant from becoming the worst disaster in history are putting their lives on the line, working in dark and dangerous conditions in buildings with collapsed walls and roofs, getting exposures in a single hour that most of us will not see in an entire year.
The long term impacts of lower levels of exposure to nuclear radiation remains a subject of intense speculation that has not received the attention that it merits. A lifetime study carried out for more than half a century found men born in the 1960s who died from cancer in middle age had twice as much radioactive strontium in their baby teeth compared to those who were still alive.
One would think that a nation committed to nuclear energy would also be committed to conducting serious studies of the matter. It would not be hard to analyze baby teeth from different time periods for changes in their radiation levels and see if these are tied with other health issues. But, it might prove inconvenient.
At Fukoshima, there are reports that a fire in the spent fuel storage area has been quenched, but the water covering this is boiling into the environment through cracked walls and collapsed roofs, releasing a tremendous amount of steam laden with radioactive particles. Workers will be rotating shifts because many have already received several years of exposure in a few days. As with Hiroshima and Nagasaki, and Chernobyl, the full impact of Fukoshima will only be known decades from now, hopefully without the blackouts of information that surrounded those events for years.
Weather forecasts project that this radioactive cloud from the roiling reactor will drift out to sea. A shift in the winds could send this massive plume directly over Tokyo’s 13 million residents. While the risk to any single individual in the city will be small it will not be zero and it will be decades before any cancer toll can be detected. Those living close to the plant may be much less fortunate. They’ve been told to shelter in place, stay indoors, and seal up their homes. But, many of them no longer have homes in which to seek cover. Let’s pray that the winds are kind to Japan, during these difficult days.
Background information on radiation exposure
Life on earth has evolved with radiation over millions of years. Scientists estimate that each year people are exposed to about 1 to 5 millisieverts of radiation from the sun cosmic radiation and radon gas from the earth. As a comparison, one X-ray gives off 400 to 600 microsieverts of radiation. A whole body CT scan gives a much higher radiation dose — about 15 to 20 millisieverts, while a single organ CT involves a dose of about 10 millisieverts.
Inside the Fukushima plant, the radiation levels have risen dramatically, reaching the equivalent of a CT scan in an hour, according to Japan’s nuclear safety agency.
Right after the blasts on Tuesday, one hour’s exposure ran 20 times the levels allowed for nuclear plant workers in an entire year: 400 millisieverts an hour — about the same as getting 230 chest x-rays at once.
While individual responses will vary depending on age, nutritional status and health conditions, in order to develop radiation sickness, one would have to receive a one-time dose of at least 1 to 2 Sieverts. That’s 1,000 to 2,000 millisievert (mSv). Nausea and vomiting would generally occur within 24–48 hours after such an exposure.
A severe dose of radiation would be anything over 3,500 mSv, and would bring on vomiting within an hour, as well as perhaps diarrhea, bloody vomit, high fever and eventual hair loss. Severe exposure is fatal within a month about 50 per cent of the time.
In terms of cumulative exposure, 100 millisieverts a year is the lowest level at which any increase in cancer risk is clearly evident. A cumulative 1,000 mSv over a lifetime would be expected to cause a fatal cancer many years later in five out of every 100 persons with that kind of exposure.
The population risks from the expected exposures to Tokyo are still quite low, but they are not zero. While potassium iodide can block the uptake of radioactive iodine 131 to the thyroid, absorption of other radionuclides is not as easily addressed.
Photos, top to bottom: Japan Self-Defense Force officers prepare for a clean-up at a radiation affected area in Nihonmatsu, Fukushima Prefecture in northern Japan, March 15, 2011. REUTERS/Kyodo; A baby is tested for radiation in Nihonmatsu, Fukushima Prefecture in northern Japan, March 15, 2011. REUTERS/Kyodo; Medical staff use a Geiger counter to screen a woman for possible radiation exposure at a public welfare centre in Hitachi City, Ibaraki, March 16, 2011, after she was evacuated from an area within 20km (12.4 miles) radius of the Fukushima Daiichi nuclear plant. REUTERS/Asahi Shimbun