Page 581 - Environment: The Science Behind the Stories

THE SCIENCE BEHIND THE STORY

Health Impacts 3000 Girls
of Chernobyl 2500 Boys
and Fukushima 2000

In the wake of the meltdowns at 1500
Japan’s Fukushima Daiichi nuclear Number of cases of thyroid cancer Chernobyl: 1986
power plant in 2011, Japanese authori- 1000
ties tried to keep residents safe while
medical scientists from around the 500
world rushed to study how the release
of radiation might affect human health. 0
Both looked back to lessons learned
from Chernobyl 25 years earlier. Chernobyl-area boy and his mother after 1982–1985 1986–1990 1991–1995 1996–2000 2001–2005
Determining long-term health his surgery for thyroid cancer.
impacts of radiation exposure is Year
enormously difficult, and initial attempts membrane damage, and weakening of FIGURE 1 The incidence of thyroid cancer
to predict Fukushima’s health impacts the immune system. In total, 28 people in girls and boys below age 18 began
have stirred vigorous debate. Most died from ARS soon after the accident. rising in regions of Ukraine, Belarus, and
scientists expect that the reactor Those who died had the greatest esti- Russia that experienced the heaviest fall-
failures at Fukushima will have less mated exposure to radiation. out of radioactive iodine from Chernobyl.
severe health consequences than those The major health consequence Data from U.N. Scientific Committee on the Effects
at Chernobyl, because less radiation of Chernobyl’s radiation, however, has of Atomic Radiation, 2008. Sources and effects of
was emitted at Fukushima and because been thyroid cancer in children. The ionizing radiation, Vol. 2. New York, 2011.
most of it drifted over the ocean away thyroid gland is where our bodies con-
from populated areas (see Figure 20.10b centrate iodine, and one of the most has a high success rate, so as of that
and pp. 44–45). However, judging common radioactive isotopes released time, only 15 children had died from it.
Fukushima’s impacts will be challenging early in the disaster was iodine-131 Studies addressing other health
and will require long-term study. ( I). Children have large and active aspects of the accident have found
131
Let’s turn first to Chernobyl. The thyroid glands, so they are especially limited impact. Some research has
hundreds of researchers who have vulnerable to thyroid cancer induced by shown an increase in cataracts due to
tried to pin down Chernobyl’s health radioisotopes. radiation, especially among emergency
impacts have sometimes differed in Predicting that thyroid cancer workers. But neither the WHO nor U.N.
their conclusions. In an effort to reach might be a problem, medical workers assessments found evidence that rates
consensus, the World Health Organiza- measured iodine activity in the thyroid of leukemia or any other cancer (aside
tion (WHO) engaged 100 experts to glands of several hundred thousand from thyroid cancer) had risen among
review all studies through 2006 and people in Russia, Ukraine, and Belarus people exposed to Chernobyl’s radia-
issue a report summarizing what scien- following the accident. They also meas- tion. Still, some cancers may appear
tists had learned in the 20 years since ured food contamination and surveyed decades after exposure, so it is possible
the accident. In 2008, a United Nations people on their food consumption. that many illnesses have yet to arise.
committee issued a comprehensive These data showed that drinking milk Moreover, conducting epidemiological
report as well. from cows that had grazed on con- studies (pp. 393–394) with enough sta-
The most severe effects were taminated grass was the main route of tistical power to detect minor increases
documented in emergency workers exposure to I, although fresh vegeta- in rare events requires observing huge
131
who battled to contain the incident in bles also contributed. numbers of people over many years.
its initial days. Medical staff treated and As doctors had feared, rates of When the Fukushima crisis struck,
recorded the progress of 134 work- thyroid cancer rose among children in Japanese authorities applied lessons
ers hospitalized with acute radiation regions of highest exposure (FIGURE 1). from Chernobyl. They provided iodine
sickness (ARS). Radiation destroys Multiple studies found linear dose- tablets to young people evacuated from
cells in the body, and if the destruction response relationships (p. 394) in data the region and they restricted agriculture
outpaces the body’s abilities to repair from Ukraine and Belarus. By 2006, near the plant, stopping contaminated
the damage, the person will soon die. medical professionals estimated the food and milk from entering the market.
Symptoms of ARS include vomiting, number of cases at 6000 and rising. These measures to prevent people’s
fever, diarrhea, thermal burns, mucous Fortunately, treatment of thyroid cancer uptake of iodine-131 apparently were

580

M20_WITH7428_05_SE_C20.indd 580 13/12/14 1:56 PM