Radiation risks of the Fukushima nuclear accident, expressed as slices of bacon

If we must die . . .

Because I apparently enjoy banging my head against brick walls and similarly productive activities, I commonly place myself in the path of rampaging internet mobs, calling for humility, moderation, and tolerance (hypocrisy being one of my other defects of character.)

Nuclear energy in the United States is, by far, the largest single source of low-carbon energy. Nuclear energy production has been flat in the United States for the last ten years, even as the need for more low-carbon electricity has become screamingly apparent, partly because these plants tend to be expensive and can take a very long time to build, but in large part because these plants are very unpopular, due to fear of nuclear radiation.

Nuclear kWh -- flat as a day-old soda

Nuclear advocates don't always respond to these concerns in the best way. Besides pointing out that these risks are often overstated, a fair number of them foolishly try to deny that ionizing radiation from nuclear accidents or improperly stored waste could cause any harm at all, justifying that counterintuitive conclusion with misreadings of the epidemiological literature or with reference to pseudoscience like radiation hormesis.

The truth is that the cancer risk of low-level exposure is real, but very, very small. Since the cancer risk of red and processed meats are in the news -- sometimes being similarly exaggerated -- I wondered if one could express the risks of the Fukushima nuclear accident in terms of an equivalent number of slices of bacon.

Ten thousand people living close to the Fukushima plant, tested in this study, were exposed to as much as 1.07 mSv of internal radiation (one person) [1]. The average was less than that. They don't directly give the average or the means to calculate it in the paper, but judging by these graphs, and by the fact that two-thirds of adults had no detectable internal radiation exposure at all, we can estimate the average at less than 0.25 mSv. One mSv carries with it an additional risk of death from cancer of 0.005%.

Doctors and researchers are still trying to sort out the cancer risks, if any, from non-charred red meat. Processed meats, like bacon, are definitely associated with distal colon and rectal cancer. There may be other cancer risks, such as gastric cancer, but these are so small that scientists are still arguing about them. The only significant risk (other than that associated with excess calorie consumption, i.e., obesity and its diseases, and hypertension from excess sodium in susceptible individuals) is from colorectal cancer. Two slices of bacon per week carry with them a 47% increase in the risk of death from colorectal cancer, which in Americans is 15.5/100,000 = 0.0155% risk of death.

0.0155% * 0.47 = 0.007285%

But this is meat consumption over the long term, so we will give our hypothetical colon cancer victim 30 good years of bacon consumption before succumbing -- 0.007285/(30 * 52) = 0.00000466987% excess risk of death from colon cancer per serving. 1 mSv is approximately 0.005%, so 0.00005/
0.0000000466987 = 1070 slices of bacon.

One civilian in the "hot zone" at Fukushima was subjected to an excess cancer risk comparable to three slices of bacon with breakfast daily for a year. The average exposure in the hot zone was on the order of two slices daily for four months.

I suggest slices of bacon as a new standard method of describing radiation risks from nuclear energy. Real, but small. 

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1. External exposure is more variable and harder to measure, but this study found 2/3 of external exposures were less than 1 mSv, and 98% were less than 10 mSv. 10 mSv is a good bit of bacon -- 3 slices a day for ten years -- but still less than a single abdominal CT. 98%, again, were below that, and 2/3 were less than a tenth of that.