Tuesday, March 29, 2011

The Uncertainty of the Impact of Radiation - Fukushima

The impact of Fukushima's radioactive fallout will be compared to three major things, background radiation, Three Mile Island and Chernobyl. The actual long term impact cannot be exactly stated. Statistical probabilities with levels of uncertainty will be used to estimate the impact. Statistical methodology is a powerful mathematical tool in the proper hands and powerful propaganda tool in the hands of the biased or poorly trained. Abuse of statistics is unfortunately all too common.

Mrs. Cindy Folker, was recently on C-Span stating her concerns about nuclear power. She stated basically, that it is not the job of the public to prove the dangers of radiation, but the job of the government to disprove the danger of radiation due to nuclear power. She is partially right. It is the job of the government to state the statistical probability of health impacts of radiation by type, source and exposure. To Mrs. Folker, there is no safe level of radiation. While that is probably true, there is no way to avoid exposure to radiation.

Everyone will make their own determination of the potential danger of radiation. Some will make total uninformed determinations, some will study to become informed before making a decision. The major problem is that many outspoken, caring and passionate people will sway the opinion of many with often uninformed, biased and passionate rhetoric. Often the sources they site, if indeed they site sources, are biased to their opinion. Not intentionally, it is human nature. You are more likely to find and believe what you expect to exist than what may exist. This is one of the major problems with statistical methodology.

Mrs. Folker referenced two TMI studies. From Wikipedia, this is the opening paragraph,
"The health effects of the 1979 Three Mile Island nuclear accident are widely, but not universally, agreed to be very low level. According to the official radiation release figures, average local radiation exposure was equivalent to a chest X-ray, and maximum local exposure equivalent to less than a year's background radiation. Local activism based on anecdotal reports of negative health effects led to scientific studies being commissioned. A variety of studies have been unable to conclude that the accident had substantial health effects, but a debate remains about some key data (such as the amount of radiation released, and where it went) and gaps in the literature."

For all its faults, Wikipedia is an easy source and generally fairly accurate. The "not universally agreed" sources are the ones Mrs. Folker cited, quite passionately. If conspiracies are your cup of tea, there is no way that you can make an informed decision, so you may as well find something else to read.

One of the sources, again per Wikipedia, Dr. Steven Wing was hired by lawyers for 2000 residents of the TMI area to perform a study to counter the government's study. "Wing found cancer rates raised within a 10-mile radius two years after the accident by 0.034% +/- 0.013%, 0.103% +/- 0.035%, and 0.139% +/- 0.073% for all cancer, lung cancer, and leukemia, respectively.[15] An exchange of published responses between Wing and the Columbia team followed." Dr. Wing's report conclude that a small but statistically significant increase in cancers in the TMI area was evident.

At the Columbia team's recommendation another study was performed by the University of Pittsburg which found a slight increase in mortality but no direct attribution of causation to TMI radiation. To which Dr. Wing responded, "Wing et al. criticized the Pittsburgh study for making the same assumption as Columbia: that the official statistics on low doses of radiation were correct - leading to a study "in which the null hypothesis cannot be rejected due to a priori assumptions."[20] Hatch et al. noted that their assumption had been backed up by dosimeter data,[17] though Wing et al. noted the incompleteness of this data, particularly for releases early on."

In 2005,there was another study concluding, "In 2005 R. William Field, an epidemiologist at the University of Iowa, who first described radioactive contamination of the wild food chain from the accident[citation needed] suggested that some of the increased cancer rates noted around TMI were related to the area's very high levels of natural radon, noting that according to a 1994 EPA study, the Pennsylvania counties around TMI have the highest regional screening radon concentrations in the 38 states surveyed."

Then in 2008 as study often quoted by nuclear power advocates, "A 2008 study on thyroid cancer in the region found rates as expected in the county in which the reactor is located, and significantly higher than expected rates in two neighbouring counties beginning in 1990 and 1995 respectively. The research notes that "These findings, however, do not provide a causal link to the TMI accident."[23] Mangano (2004) notes three large gaps in the literature: no study has focused on infant mortality data, or on data from outside the 10-mile zone, or on radioisotopes other than iodine, krypton, and xenon.[4]"

The note of "no study focused on infant mortality data." ", the Pennsylvania Department of Health, examining death rates within the 10-mile area around TMI for the 6 months after the accident, said that the TMI-2 accident did not cause local deaths of infants or fetuses." While there may not have been a follow up study, the basic data would be available at the Pennsylvania Department of Vital Statistics should you wish to form your own opinion.

The passionate statements of Mrs. Folker are not supported by evidence. She did not even provide the results of the sources she sited with the margin of error nor mention the higher than normal background Radon concentration of the areas surrounding TMI.

There will be many passionate pleas from all segments of society. Passionate pleas with no basis in fact are useless for making informed decisions. It is likely that the impact of Fukushima will be greater than TMI. The question is, when the data is available, will rational, informed decisions be made?

If you would like another opinion.

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