Radiation Explained

[Guest guest]

Radiation's Enduring Afterglow By GEORGE JOHNSON

Becquerels, sieverts, curies, roentgens, rads and rems. For all the esoteric

nomenclature scientists have devised to parse the effects of nuclear emanations,

the unit they so often fall back on is the old-fashioned chest X-ray.

Early in the crisis at the Fukushima Daiichi nuclear power plant in Japan,

neighbors were informed with absurd precision that the radioactivity in a liter

of their drinking water had risen to the equivalent of 1/88th of a chest X-ray.

One day last week the air in Tokyo registered 0.155 of a microsievert an hour —

another chest X-ray, if you were confined for a month at that level. Though

stretched to the point of meaninglessness, the analogy is meant to soothe — balm

for a spirit burdened by a century of living uneasily with radiation.

Measured by sheer fury, the magnitude 9.0 earthquake that damaged the reactors

was mightier than millions of Hiroshima bombs. It shoved the northeastern coast

of Japan eastward and unleashed a tsunami that wiped civilization from the

coast. But explosive power comes and goes in an instant. It is something the

brain can process.

With radiation, the terror lies in the abstraction. It kills incrementally —

slowly, diffusely, invisibly. " Afterheat, " Socolow, a Princeton

University professor, called it in an essay for the Bulletin of the Atomic

Scientists, " the fire that you can't put out. "

Nuclear scientists speak in terms of half-life, the time it takes for random

disintegrations to reduce a radioactive sample to half its size. Then a quarter,

an eighth, a 16th — whether measured in microseconds or eons, the mathematical

progression never ends.

When traces of radioactive iodine were found last week in the drinking water in

Tokyo, officials expressed the danger in becquerels, the number of nuclear

disintegrations per second: 210 per liter, safe for adults but high enough to

warn that infants should not drink it. As the government began distributing

bottled water, the level fell significantly but not the fear. As far away as

California there was a run on fallout detectors.

As these hypothetical microthreats ate at the mind, rescue workers were piling

up real bodies — 10,000 so far — killed by crushing waves or their aftereffects,

deaths caused by gravity, not nuclear forces. These dead will be tabulated,

mourned and eventually forgotten. The toll will converge on a finite number.

In Chernobyl, the site of the world's previous big nuclear accident, the

counting continues, like languid ticks from a Geiger counter. A United Nations

study in 2005 concluded that about 50 people had been killed by the meltdown but

that 4,000 would ultimately die from radiation-caused cancer — victims who do

not know who they are. The most debilitating effect, one investigator said, has

been " a paralyzing fatalism, " a malaise brought on by an alien presence that

almost seems alive.

Radiation, before we had a hand in it, was just another phenomenon. Life evolved

unknowingly in its presence, with rays from the sky and earth jostling

chromosomes and helping to shuffle the genetic deck. When our brains evolved to

the point where we could measure and summon the effect, the first reaction was

not fear but fascination. The discoverers were revered as heroes. Then their

names were converted into mathematical units.

Roentgen produced the first artificial X-rays in 1895, tantalizing the

world with see-through images of his wife's hand, then Henri Becquerel found

similar emissions coming unbidden from uranium. Isolating the first minuscule

specks of radium, Marie Curie, the greatest of the pioneers (1 curie = 37

gigabecquerels), marveled that its eerie blue glow " looked like faint, fairy

lights. " She was seeing the optical equivalent of a sonic boom — contrails of

photons produced by speeding particles. Eager to see this new world for

themselves, people purchased small brass eyepieces called spinthariscopes, named

for the Greek word for spark. Mounted inside was a bit of radium bombarding a

scintillating screen. Hold it to your eye and behold the tiny explosions.

Spinthariscopes sat on parlor shelves next to stereoscopic postcard viewers and

kaleidoscopes, items in a cabinet of curiosities.

Radiation was even supposed to be good for you. Vacationers soaked in radium hot

springs. Magazines carried advertisements for radium suppositories, radium

toothpaste and radium bread — quack products ranging from useless to harmful. As

late as the 1950s, customers could peer inside their own feet through shoe store

X-ray machines, the scientific way to ensure a perfect fit.

As more bona fide uses led to a medical revolution — X-rays for medical imaging,

radium for killing rapidly dividing cancer cells — hints of danger gradually

accumulated. In the 1920s, women who had painted glow-in-the-dark radium watch

dials began to sicken and die. Around the same time, scientists experimenting

with fruit flies showed that radiation causes genetic mutations — red eyes

turned to white.

With Hiroshima, Nagasaki and above-ground testing, everything nuclear began to

take on a more sinister air. But the threat still seemed distant and surreal. As

mothers worried about strontium-90 from fallout insinuating its way into their

children's bones, they were reading " Atomic Bunny " comic books and sending in

cereal box tops for the Lone Ranger Atomic Bomb Ring, a cheap plastic

spinthariscope that promised a glimpse of " genuine atoms split to smithereens. "

For all the dread evoked by the stockpiling of nuclear weapons, it was the 1979

accident at Three Mile Island that marked an abrupt turn. Just days earlier,

" The China Syndrome " had its cinematic release. The " backup systems to backup

systems to backup systems " Jack Lemmon boasted about to Jane Fonda crumpled on

the screen, adding to the anxiety over what was happening outside. In the end

the partial meltdown was contained and the damage was mostly economic. A

postmortem by the American Nuclear Society reported that the average dose to

people living within 10 miles of the accident was 0.8 of a chest X-ray. But the

name Three Mile Island never lost its afterglow.

In the meantime, Chernobyl has become a tourist destination. Visitors board a

bus in Kiev and cross the border of the " zone of estrangement. " Avoiding the

remaining hot spots, they see the ghost city of Pripyat and the ruined reactor.

They can feed catfish swimming in a reactor cooling pond, and none of them have

three eyes.

They might also see a resurgence of wildlife: moose, roe deer, Russian wild

boar, foxes, river otter and rabbits. American ecologists who conducted a study

of the area in the late 1990s concluded that for all the harm caused by fallout,

the biggest impact from humans has been positive: their decision to pack up and

leave. " Northern Ukraine is the cleanest part of the nation, " an official of

Ukraine's Academy of Sciences said at the time. " It has only radiation. "

Only radiation. That is small consolation for the evacuees in Japan and the

workers, still dousing the reactors with hoses as though fighting a fire that

could be put out.

, a former reporter and editor at The Times, is author of " The Ten

Most Beautiful Experiments. " He is writing a book about cancer.

http://www.nytimes.com/2011/03/27/weekinreview/27johnson.html