Radiation Metrics and the Media Confusion Fuels Public Fears

Transcription

1 Radiation Metrics and the Media Confusion Fuels Public Fears

2 Radiation Metrics and the Media Confusion Fuels Public Fears THREE MAIN POINTS Journalists neither know nor CARE about the units by which radiation is measured. They care about what their readers/viewers/listeners care about; the RISK to health. Any information about radiation metrics for media use MUST put the information in the context of what it means to health risk. Failure to do so feeds media/public confusion and fear.

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4 4 th paragraph Risk Fear, fueled by the popular perception of radiation risks and the slow response to the fire by landfill operator Republic Services and the Environmental Protection Agency, has stoked conflict and distrust

5 7 th, 8 th paragraphs Risk The waste emits only tiny amounts of the gamma rays that can penetrate all but the most dense material, including the human body. Instead, almost all of the radiation released by the waste comes in the form of alpha particles, radiation that can t pierce the skin and needs to get inside the body to do damage. Asked to review measurements of radionuclides in the West Lake landfill and Coldwater Creek gathered by regulators, Sasa Mutic, the director of radiation oncology physics at Washington University School of medicine, indicated the risks from exposure are akin to driving a car.

6 9 th paragraph first reference to dose metrics After years of testing, the highest concentration of contamination the EPA has detected near the surface of West lake would require ingesting over an ounce to deliver the same radiation dose as a whole-body CT scan, according to dose calculations from the international Commission on Radiological Protection and reviewed by experts. The dose from a whole-body CT scan, according to the National Research Council, a nonprofit institution that produces reports reflecting the scientific community s views, would be expected to cause a 1 in 1,000 risk of cancer

7 10 th paragraph, metric reference framed in terms of risk But the highest radionuclide concentrations in West Lake are not the norm, and many of the higher readings are dozens of feet underground. With most dirt at West Lake, it would take ingesting a least a quarter-pound, if not more, to deliver a CT scan s worth of radiation, according to EPA estimates of average concentrations.

8 26 th, 28 th paragraphs first reference to units, framed as RISK Radiation doses are usually expressed in millirems or milliseiverts. The average American typically receives about 320 millirem of natural radiation, or 3.2 milliseiverts, annually. The atomic bomb survivors, on average, received about 120 milliseiverts of radiation, or 12,000 millirem, Royal said. That s about 12 CT scans all at once.

9 30 th graph, risk per units The National Research Council s lifetime risk model estimates that one person in 1,000 would be expected to develop cancer if he or she were exposed to an additional 1,000 millirem, or 10 milliseiverts, of radiation, about as much as a whole-body CT scan

10 32 nd paragraph The confusion of a DIFFERENT unit The concentrations of those materials in the West Lake Landfill are measured in picocuries. When doctors use radioactive elements in tests or treatment, the unit we use is millicuries Royal said. Even the most contaminated portions near the surface of West lake contain only about 30,000 picocuries per gram of thorium, or millicuries. The concentrations of radium and uranium are lower still

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12 5 th, 6 th paragraphs Units, to describe RISK But questions remain about whether radiation levels are low enough for all residents to return. On Friday morning, for example, the entrance to Minamisoma city s main hospital measured 0.51 microseiverts per hour in radiation, according to numbers released daily by the city. A simple calculation would bring annual exposure at the level to almost 4,500 microseiverts, or 4.5 milliseiverts a year, far above the annual limit of 1 milliseivert for civilians that is recommended by the International Commission on Radiological protection. (If, of course, you stood in that doorway for a year!)

13 7 th paragraph risk per unit (Uncertainty feeds fear.) While experts say these levels are still low the limit for radiation workers in the united States is 50 milliseiverts per year, for example little is known about the health effects of extended exposure to low level radiation. Moreover, children and pregnant women are known to be especially sensitive to radiation. A seivert measures the effect of radiation on the human body.

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15 IAEA/INES scale Big numbers are scary, no clarity on risk/units this upgrade to level 3 ( Serious incident ) means the event involves the release of a few thousand terabecquerels of activity into an area not expected by design which requires corrective action, or one resulting in radiation rates of greater than one seivert per hour in an operating area, according to the INES user s manual. A terabecquerel is 1 trillion becquerels, defined as the radioactive decay of one nucleus per second; a seivert is a unit of biological radiation dose equivalent to about. 50,000 front view chest X rays

16 LiveScience article Immediately after the June 2011 meltdown, scientists measured that 5,000 to 15,000 terabecquerels of radioactive materials was reaching the ocean. The biggest threat at that time was from radioactive cesium. But for leaks that enter the ground, the radionuclides strontium and tritium pose more of a threat, because cesium is absorbed by the soil while the other two are not. The Tokyo Electric Power Plant (TEPCO) estimated that since the March 2011 disaster, between 20 trillion and 40 trillion becquerels of radioactive tritium have leaked into the ocean

17 New Yorker article The most radioactive place in New York City.

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19 UNSCEAR document Radiation Effects and Sources (specific dose numbers)

20 UNSCEAR Radiation Effects and Sources (specific dose numbers)

21 UNSCEAR Radiation Effects and Sources (no specific dose numbers on X axis)

22 UNSCEAR Radiation Effects and Sources (Gy? Other slides were in Sv.)

23 Radiation Metrics and the Media Confusion Fuels Public Fears THREE MAIN POINTS Journalists neither know nor CARE about the units by which radiation is measured. They care about what their readers/viewers/listeners care about; the RISK to health. Any information about radiation metrics for media use MUST put the information in the context of what it means to health risk. Failure to do so feeds media/public confusion and fear.