Risk from radiation very small (James Conca, Forbes.com)

Link: http://www.forbes.com/sites/jamesconca/2016/06/24/radiation-poses-littlerisk-to-the-world/#366482a348b5 This is an excerpt. For complete text and embedded hyperlinks, see address above.

World-Wide Risk From Radiation Very Small

by James Conca June 24, 2016 It is very difficult, and very rare, for anyone to be hurt by any dose of radiation obtainable in our society.

Contrary to the hype of Fukushima, and even Chernobyl, the observable radiation health effects from both accidents were small. In the case of Fukushima, it was as close to zero as one can get. In the case of Chernobyl, it was still very small.

The reason you might not know this, is that almost everyone uses the wrong model to predict health effects from radiation at these levels, and only recently have the global health, nuclear and radiation agencies realized that error and are moving to correct. However, as with most scientists, this change has been quiet and sort of cloaked in scientific jargon. It’s also very political since it involves a lot of money and has spanned a lot of time.

But the implications are enormous.

The latest scientific society to make clear that we have been doing this wrong is probably the most qualified to understand this issue – the Health Physics Society. The Health Physics Society is the scientific society that includes radiation protection scientists. And they recently put out a revised position statement on Radiation Risk In Perspective. In it, they advise against estimating health risks to people from exposures to ionizing radiation that are anywhere near natural background levels because statistical uncertainties at these low levels are great.

In other words, any possible adverse health effects resulting from radiation doses below 10,000 mrem (100 mSv) are not detectable.

Background radiation across the Earth varies from 3 mrem/yr (0.03 mSv/yr) over the oceans to 10,000 mrem/yr (100 mSv/yr) in areas of high elevation made up of granitic rocks. Thus, it is not surprising that populations subjected to radiation levels page 1

of 10,000 mrem (100 mSv) or below, either natural or man-made, show radiation effects that are not statistically different from zero. .. .. ..

As an example, in a general population of 100,000 people in the United States, about 40,000 ± 1,600 people will naturally develop cancer over their lives with no help from radiation. If you subject this same population to radiation levels ten times their normal radiation levels, 40,000 ± 1,600 will develop cancer over their lives.

There will be no difference.

Of course, there could be a few dozen cases hiding in that huge error bar – that plus or minus 1,600 that is the margin of error – but by definition those will be statistically insignificant and should not be any cause for concern. They’re too few to ever be measured. The concern should be for the 40,000 natural cancers.

The reason for this 60-year overreaction is this incorrect model, called the Linear NoThreshold dose hypothesis. LNT is used in radiation protection to quantify radiation exposure and set regulatory limits. First put forward after WWII, LNT assumes that the long term, biological damage caused by ionizing radiation (primarily the cancer risk) is directly proportional to the dose – increase the dose, increase the risk, increase the cancers, increase the deaths. But this model just sums exposure to all radiation, without taking into account dose levels or dose rates, or the fact that organisms have immune systems that are very effective at repairing cellular damage from normal doses of radiation.

So LNT assumes that radiation is always considered harmful with no threshold below which there is no harm, and the sum of several very small exposures are considered to have the same effect as one larger exposure. But even assuming LNT, the risk is still very, very small for anything below 10,000 mrem/yr (100 mSv/yr).

The usual example of LNT and its cumulative effective dose concept is that if 1000 aspirins taken at once would kill the average person (it certainly would!), then the same person would be killed by taking 1000 aspirin at the rate of one a day for page 2

1000 days. Also, if on one particular day, 1000 people each took one aspirin, then one of those thousand people would die.

Obviously, we know this is completely wrong.

One of the earliest applications of LNT was to interpreting the increase in cancer rates of the Japanese Atomic Bomb Survivors (see figure). The figure graphs the solid cancer occurrences in the survivors against acute radiation dose using data from the International Commission on Radiological Protection (ICRP 1994). Bombsurvivors received these levels as an acute dose, meaning the dose came all at once, in less than a second as the radiation burst forth from ground zero of the blast. Acute doses will have greater effects than chronic doses of the same level, because the immune system will be more overwhelmed over the shorter time span, e.g., 1000 mrem delivered in one second will have larger effects than 1000 mrem delivered over one year.

Solid Cancers per 100,000 population in the Japanese Atomic Bomb Survivor Cohort of 79,901 subjects. It is clear that high doses of radiation cause an increase in solid tumors. At low doses, there is no clear increase at all. Below 10 rem (0.1 Sv), the effects

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disappear completely in the noise – the noise of all the other environmental and genetic effects that cause death. Source: data from ICRP

It is clear from the figure that high doses of radiation cause an increase in solid tumors. At low doses, there is no increase. The part of this line above 10 rem (0.1 Sv) certainly supports the linear idea. Doses between 50 and 100 rem (0.5 and 1 Sv) resulted in a 29% increase in cancers. However, below 10 rem (0.1 Sv), any effects completely disappear in the noise – the noise of all the other environmental and genetic effects that cause cancer and death. In the 1950s, to be simplistic, the world governing bodies decided to just draw in that line anyway, all the way down to zero.

It made it easy to use and easy to make regulations. .. .. ..

We know LNT is not important for low doses. But LNT was adopted amidst the Cold War in 1959 to be what they thought was super-conservative, as a way to make policy, and as a way to stop above-ground nuclear weapons testing. Few experts considered it valid for actually predicting health effects from low levels of radiation.

However, over the years, LNT became ensconced in regulatory and policy lore even as its origins were forgotten.

Then Chernobyl happened. And this model was used incorrectly to estimate public health effects. Hundreds of thousands of people were unnecessarily evacuated because of the overestimation of adverse health effects by radiation exposure as predicted by the LNT, incurring a much larger risk from the perils of the evacuation.

As a result, many thousands of deaths occurred, not from radiation, but from panic, depression and alcoholism.

The health effects, including deaths, were thoroughly documented by the IAEA’s Chernobyl Forum September 6-7, 2005 in Vienna in their resultant report. The actual fatalities were - 2 immediate, non-radiation deaths - 28 early fatalities from radiation within 4 months, - 19 late adult fatalities from radiation over the next 20 years, and - 9 late child fatalities from radiation resulting in thyroid cancer. page 4

In addition, almost a thousand emergency workers put onsite unprepared by the Soviets in the first days of the accident received high doses of radiation, and about 50 died from cancer and other health issues.

Debate on LNT raged for 25 years following Chernobyl. Then Fukushima happened.

Again, large evacuations occurred, with deaths occurring from panic and depression, but not from any radiation, since doses to the public were so small.

After Fukushima, debate on LNT really accelerated since the United Nations, WHO and other bodies realized that using LNT to make real decisions once again failed the public (UNIS; UNSCEAR Fukushima;UNSCEAR A-68-46). Policy is beginning to change.

The U.S. Nuclear Regulatory Commission now regards the LNT hypothesis as a conservative model for estimating radiation risk while noting that public health data do not establish the occurrence of cancer following exposure to low doses and dose rates — below about 10,000 mrem (100 mSv).

Studies of occupational workers who are chronically exposed to low levels of radiation above normal background have shown no adverse biological effects. In fact, they actually show the reverse – what we called the healthy radworker syndrome that we had to invent to explain why so many radiation worker cohorts had less cancer than the general population. The ridiculous assumption was that radworkers were inherently healthier than all other workers. This idea was later debunked by comparing these workers to the correct control group., i.e., similar workers that never handled radiation, and showing that the cancer rates were the same.

In 2014, UNSCEAR, the preeminent global body on radiation effects, finally reversed its position on LNT, saying “the Committee does not recommend multiplying low doses by large numbers of individuals to estimate numbers of radiation-induced health effects within a population exposed to incremental doses at levels equivalent to or lower than natural background levels.” This was a reversal of 50 years of support for using LNT this way.

And now the Health Physics Society has weighed in to caution against using LNT to predict deaths from low-level radiation.

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With respect to Chernobyl, UNSCEAR determined after 20 years that there is no evidence of a major public health impact attributable to radiation exposure from the Chernobyl accident. Except for a possible small number of thyroid effects, the only people affected by the radiation were the radiation workers and emergency responders. Not the public.

Similarly, the disaster at the Fukushima Daiichi Power Plant following the devastating tsunami in Japan has proven costly in many ways – politically, economically and emotionally. But the feared radiation-induced cancer and death is not occurring. According to UNSCEAR, no radiological health effects have resulted from the Fukushima disaster in the public – neither cancers, deaths nor radiation sickness. No one received enough dose, even the 20,000 workers who have worked tirelessly to recover from this event.

A recently published paper in the Journal of Leukemia pointed to two important aspects of this issue: - UNSCEAR unequivocably reported that “Radiation exposure has never been demonstrated to cause hereditary effects in human populations,” a finding supported by recent research.

- the health data from Hiroshima on about 96,800 humans suggest there is an acute radiation threshold at about 50 rem (500 mSv) for excess leukemia incidence. This is consistent with the conservative threshold dose of 10 rem (100 mSv) for all cancers.

The large numbers of cancers and deaths predicted for Chernobyl and for Fukushima that have flooded the media were all generated by this incorrectlyapplied model. It is now up to the scientific community, which generally eschews political controversy, to weigh in on this subject and decide whether being ridiculously conservative is worth the pain and suffering it will cause to the public if another incident occurs.

Dr. James Conca is a geochemist, an RDD expert, a planetary geologist and professional speaker. Follow him on Twitter @jimconca and see his book at Amazon.com

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