The Banana and the Bomb

Locating risk and moral boundaries in a radioactive world.

By Tim Connor

In writing recently about the radioactive consequences of Fukushima, I made use of a banana. It was handy. A simple banana, chock full of healthy, life-giving potassium—99.988 percent of which is not radioactive.

It is the .012 percent of the potassium in the banana (potassium-40) that is radioactive that I wanted to borrow. It is a simple way to remind people that the world around them is awash in radioactivity and that nearly everything you can eat or drink has some radioactivity in it.

For the sake of word economy (it was an 8,000 word piece) there were at least a couple important issues I rushed past.

The first is an important slice of science.atomic frontier days

The second is a closer examination of the ethical dimensions of radiation exposure, and how the culture of secrecy and propaganda that came hand-in-hand with nuclear technology shaped our attitudes and fears.

First to the science.

About that Banana

One thing I could have been clearer about is that there is no reason to stop eating bananas. While it is true that a typical banana contains more than 500 picocuries of radioactivity from the long-lived (a half life of 1.3 billion years) isotope potassium-40 (K-40), what is also true is that it really doesn’t matter whether you eat bananas or not. You’re going to get the same radiation dose from K-40 either way.

This is because your body craves potassium (it is necessary to maintain the fluid balance in our cells) and if you don’t get it from bananas you will take it in from broccoli, lima beans or potatoes or any other food rich in potassium. The proportion of radioactive potassium to stable potassium is the same in bananas as it is in everything else. Moreover, your body exercises homeostatic control over your potassium content and regulates the balance independent of the potassium in your diet or in the environment.

Whether it is from bananas or any other source, an adult male retains enough potassium that even the tiny fraction of potassium that is radioactive (measuring roughly 100,000 picocuries) delivers a combined 32 millirem (mrem) annual radiation dose to bone and soft tissue.

This is not a trivial amount of radiation. It’s about 10 percent of the annual dose an average person receives from natural sources and actually eight times the internal dose allowed under the federal drinking water standard (4 mrem per year) for radionuclides.

But, here’s the important point: you and I can’t possibly prevent, let alone regulate, this exposure. Potassium is literally the stardust that we’re all made of (it is created in supernova explosions) and the radiation dose you receive from potassium-40 is just a part of life as long as the human body needs potassium. You can worry about the radiation dose if you choose, but you should not worry about eating a banana, because, again, you’ll get the dose whether you eat bananas or not.

The Silent Killer in your Basement

Aside from x-rays and other medical procedures—which are major contributors to radiation dose and can easily account for 100 mrem+ doses per year—the major portion of avoidable radiation exposure is, by far, radon gas. This is especially true in the inland Northwest. Unlike exposure to the radiation emanating from potassium-40, radiation doses from radon gas are largely avoidable, and very much worth making efforts to avoid.

Radon comes from the decay of uranium and thorium in the earth’s crust. As I noted in the Fukushima piece, radon gas inhalation is the second leading cause of lung cancer in the U.S., causing between 15,000 and 22,000 lung cancer fatalities per year, according to the National Academy of Sciences.

Even though natural events can be terrifyingly unpredictable and lethal, we accept them without outrage. It is not as though the Earth has a slick public relations firm that broadcasts advertisements, trying to convince us that inhaling radon will enhance our sex appeal.

The risk is not uniform. Even though the national average dose from indoor radon is 200 mrem per year, local geology is a key factor. There are uranium mines in northeastern Washington, so it shouldn’t come as a surprise the region has a serious radon problem. Whereas the average concentration of radon in homes nationally is 1.3 picocuries per liter (pCi/L) of air (resulting in the national 200 mrem average annual dose from radon) the average concentration in Spokane County is 9 pCi/L, with some measurements reaching well into the hundreds of picocuries per liter. (One can easily imagine the uproar if, instead of Mother Nature, Hanford or a mining company were responsible for subjecting people in Spokane to such large doses of a silent killer, because that’s what radon is.)

In direct terms, what this means is people should measure the radon gas levels in their homes. (Radon detection kits are readily available under $50.) This is especially true if you have children who are sleeping or spending a lot of time in basements into which the odorless, invisible gas can seep. Again, even a 1 pCi/L concentration level can result in a significant radiation dose.

Plutonium? Meet Polonium…

There is, of course, a big difference in the iconography of a banana and a mushroom cloud. One exemplifies innocence, the other menace.

But, in terms of the dangers and risks they pose, are there any significant differences between the man-made radioactive hazards and those that occur naturally?

Yes and no.

Hanford's B Reactor, where plutonium for both the "Trinity" test and the Nagasaki bomb was created.
Hanford’s B Reactor, where plutonium for both the “Trinity” test and the Nagasaki bomb was created.

Certainly there is nothing earthly that replicates the burst of deadly neutrons unleashed by a designed nuclear explosion or the fissioning process in a nuclear reactor. Neutron radiation certainly caused most of the acute radiation deaths at Hiroshima and Nagasaki and also led to increased cancers and other long-term health effects among the Hibakusha—the surviving victims of those bombings.

But are the man-made radionuclides created in nuclear detonations or reactors qualitatively more harmful than naturally occurring radionuclides? That’s a much tougher call.

For the argument that there is a qualitative difference, plutonium is perhaps the best example. Glenn Seaborg, the chemist whose team at California-Berkeley first created and isolated plutonium, was unpleasantly surprised to discover, over time, just how “fiendishly toxic” it is. Plutonium ejects alpha particle radiation (consisting of two protons and neutrons) which does much more damage than other forms of ionizing radiation (neutron, gamma, beta) once the alpha-emitting radionuclide is deposited inside the body.

We think of low-level radiation as a stochastic killer—with the long-term fatalities (largely cancers) being the result of a random probability distribution where risk increases in  proportion with dose. The exception is a situation like that which occurred during the early hours of the Chernobyl reactor accident where more than thirty firemen and other plant workers trying to extinguish the reactor received lethal doses from acute radiation poisoning. Yet, mere specks of plutonium can be just as deadly. Renowned radiation health scientist John Gofman calculated that an inhaled dose of just 112 millionths of a gram of plutonium would result in lung cancer 100 percent of the time.

Plutonium, of course, was the unholy grail of the U.S. nuclear weapons program, beginning with the “Trinity” explosion in Alamogordo, N.M. in July 1945. To create it and distill it in useable quantities (which is what Hanford’s labyrinthine factories were built to do) creates a witches’ brew of highly radioactive byproducts, including strontium-90 and cesium-137, both of which are biologically active, and both of which are abundant in weapons test fallout as well as the releases from Chernobyl and Fukushima.

Because it so similar, chemically, to calcium, strontium-90 is a potent bone-seeking radionuclide. Indeed, it was the ability of dissident scientists to measure Sr-90 in babies teeth  that helped push the U.S. into negotiating with the Soviet Union to cease atmospheric nuclear weapons tests in the early 1960s. Strontium-90 is of serious concern in the aftermath of the Fukushima tragedy because (as experience at Hanford first indicated) it travels readily with groundwater and is retained for very long periods in the bones and shells of organisms.

So, yes, there is solid evidence that man-made radioactive elements and isotopes pose (and have caused) serious and potentially lethal risks to humans. But the evidence that these radioactive materials are categorically more lethal than naturally occurring radionuclides is slender.

We don’t think of tobacco companies as delivering more radiation deaths, by far, than the nation’s nuclear power industry. Yet, that’s what the science and the math clearly indicate. It’s a puzzle as to why more of us don’t know this.

Polonium-210, for example, is a naturally occurring but intensely radioactive isotope—literally the last radioactive isotope in the long decay chain of uranium-238 before it calms into non-radioactive lead. It gives off so much alpha radiation that a capsule containing merely half a gram of Po-210 will spontaneously reach a temperature of 500 degrees Celsius.  There’s a reason it was the poison of choice when someone decided to kill dissident writer and former Russian spy Alexander Litvenenko in November 2006, after Litvenenko had been granted asylum to live in Britain. There aren’t many cases where radioactive substances are used for cold-blooded murder, but this is one of them.

Granted, it takes human instruments and purposes to produce polonium-210 in concentrations of the sort used to kill Litvenenko. But even in natural concentrations Po-210 is a gruesome killer. Because dust particles containing trace amounts of Po-210 get attached to naturally sticky tobacco leaves, tobacco smoke is significantly radioactive.  By one authoritative estimate,  a typical smoker will receive an effective dose equivalent of 1,300 mrem annually from the naturally occurring polonium-210 in cigarette smoke, which, in turn, leads to a one in 100 risk for fatal lung cancer over a fifty period.

If this reads like a small risk, it’s not, especially when you consider there are 42 million smokers, just in the U.S. alone. Indeed, the National Council on Radiation Protection and Measurements makes a poignant observation—that the radiation doses from Po-210 in cigarette smoke are probably the “greatest single contributor” to overall population dose, including radiation from all other natural sources and medical procedures as well.

We don’t think of tobacco companies as delivering more radiation deaths, by far, than the nation’s nuclear power industry. Yet, that’s what the science and the math clearly indicate. It’s a puzzle as to why more of us don’t know this, and perhaps it’s because we have already glued together an uneasy social compact, of sorts, around the evils of tobacco. It would be a deadly (nicotine, tar, benzopyrene, etc.), expensive habit and societal plague  even without the radioactive garnish of polonium-210.

Meet the Devil

My mother had just turned 12 when her older brother ran through their home in Pasco, Washington, exclaiming that Hanford was about atomic bombs. This was August 6, 1945, the day Hiroshima was largely obliterated by a single bomb dropped from a B-29. Three days later, a small sphere of Hanford plutonium was similarly detonated upon Nagasaki.

Pasco is but a few miles downstream of Hanford on the Columbia River. The government’s confiscation of land followed by the immense construction activity was a focus of local conversation. But it wasn’t until the day of the Hiroshima holocaust that Hanford’s pivotal role was publicly disclosed by President Truman.  The lower Columbia basin had become so impoverished during the Great Depression that Hanford, like Grand Coulee before it, was embraced for the simple promises offered by its paychecks. And it was all gift-wrapped in propaganda and secrecy. In his statement—as Hiroshima smoldered and bled in radioactive ruin—Truman spoke of how the atomic bomb would “protect us from the danger of sudden destruction” and how “atomic power can become a powerful and forceful influence towards the maintenance of world peace.”Our friend

By that time, my mother’s family had been exposed to dangerous level’s of iodine-131 from the stacks on Hanford’s plutonium separations plants. These secret exposures would continue for years to come, as would the contamination of Pasco’s drinking water with radioactive effluent from Hanford’s reactors. Documents obtained under the Freedom of Information Act showed Hanford  officials knew about the exposures and the risks. But the site’s managers were more concerned about meeting their plutonium quotas.

Halfway around the world the same basic story was repeating itself in the Ural Mountains where the Soviet Union had built its version of Hanford, to make plutonium for its half of the nuclear arms race. Kate Brown captures both stories in her recent book Plutopia: Nuclear Families, Atomic Cities, and the Great Soviet and American Plutonium Disasters. The details of the contamination of town and villages near the Soviet’s Maiak plutonium plant are especially gruesome.

In 1977, my grandfather, Gil Hartman, died before his time from throat cancer, at age 78. My mother’s father didn’t smoke and he was a proponent of what we now call natural foods. Although I can’t prove it, I suspect the Hanford radiation in his drinking water is what led to his cancer. I also think Hanford’s radioactive iodine is what caused my mother’s hypothyroidism. But this is the bitter insidiousness of death and disease wrought by low-level radiation. “Death by lottery and burial in a deep pile of statistics,” is how I described it in the introduction to my 1997 book Burdens of Proof.

I mention this because the Hanford reporting I did in the 1980s was a wrenching homecoming (I was actually born on the Hanford site in 1956.) One of my main assignments, first as an investigative reporter and then as a staff researcher for a public interest group, was to dig out Hanford’s secret emissions. That exercise brought me face-to-face with the unspoken policy that people like my grandfather and mom were expendable, or at least far less important to our government than the dark arts of making nuclear weapons.

The government and its contractors did this on a much wider scale, of course, and it is one of those lasting stains in our history. For example, scientists have known for nearly a century and a half about the dangers of lung cancer (caused by radon exposure in confined mine tunnels) to hard rock miners. Yet, without warning or protecting them, U.S. officials encouraged thousands of miners to tunnel for uranium (the raw fuel both for the nuclear weapons program and the then-young nuclear power industry) in mines.

For national security reasons, the U.S. Atomic Energy Commission controlled the uranium industry and even operated some of the mines itself.  AEC officials knew the mines were filled with dangerous levels of radon such that one in six of the miners working in them would be expected to get lung cancer as a result. Dr. Joseph Wagoner, an epidemiologist who studied U.S. uranium miners (many of whom were Navajo) finally resigned from the public health service, criticizing the government’s failure to protect miners as the moral equivalent of genocide.

To be sure, the radon gas in the mines was “natural” radiation. But  government officials are as culpable for these lethal exposures as they would be had they laced the workers’ food with man-made strontium-90.

There are many other examples, including how the government

Soldiers being exposed to bomb blast radiation at the Nevada Test Site in 1957,
Soldiers being exposed to bomb blast radiation at the Nevada Test Site in 1957,

shamefully neglected a quarter of a million U.S. military personnel with whom it experimented by knowingly exposing them to dangerous levels of bomb blast radiation during the years of atmospheric nuclear testing.

The overall result is not just skepticism but a deep vein of resentment and distrust. Deeper still is the bitter realization that the vast decisions to make, test, and use atomic weapons (with all the horrid consequences that ensued) were imposed by a military and political elite without any meaningful public debate. What we got, instead, were lies, stonewalling, and infantilized public relations campaigns about our tiny new friend, the atom.

By comparison, Mother Nature is guileless. Even though natural events can be terrifyingly unpredictable and lethal, we accept them without outrage. It is not as though the Earth has a slick public relations firm that broadcasts advertisements trying to convince us that inhaling radon is harmless and may even enhance our sex appeal.

It is for humans that we reserve moral judgment.

When people put other people at risk, we expect to hold them accountable not just for what they know, but what they should have known if they profess to act out of ignorance.

There will always be technical nuances (like those involving bananas and potassium-40) around issues as complicated as radiation exposure and risk. And, still, people learn from experience and through parables.

Mother Nature can break our bodies and hearts, but it takes humans to betray our trust.

sky slice


Banana and radiation symbol photos courtesy of Wikimedia images.–ed.

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