How Closely Should Radiation Be Regulated?
November 29, 2001
People are constantly exposed to radiation from natural sources. But government regulators typically act as if every bit of exposure to man-made sources of radiation -- such as from nuclear power plants -- is potentially hazardous.
So the question arises as to how much radiation exposure is harmless -- and at what level does it become harmful?
- On average, Americans are exposed to 350 millirems a year in so-called background radiation.
- The sources of this natural radiation range from cosmic radiation and radon seeping out of the earth to substances in soil, water, food and even potassium in the human body itself.
- In a report last year, the General Accounting Office said: "The standards administered by EPA and NRC to protect the public from low-level radiation exposure do not have a conclusive scientific basis, despite decades of research."
- The Environmental Protection Agency advocates a standard for all radiation exposure from a single source or site at 15 millirems a year, with no more than 4 coming from ground water -- while the Nuclear Regulatory Commission advocates 25 millirems a year from any one source.
A standard chest x-ray, by comparison, gives about 10 millirems to the chest -- which is equivalent to 1 or 2 to the whole body.
At various spots on the earth's surface, human exposure to cosmic radiation can range from roughly 100 to 200 millirems a year -- and natural variations in radiation exposure are many times the amounts that are being disputed by regulatory agencies.
Source: Gina Kolata, "For Radiation, How Much Is Too Much?" New York Times, November 27, 2001.
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