Here's a question to test how well the news media have kept the public up to date on important environmental risks. When experts studied the results of the reactor accident at Three Mile Island (TMI), they made a startling discovery. What happened there, together with data from a handful of other reactor accidents, revealed that official estimates of the danger of radioactive materials escaping in such accidents were grossly in error.
Did they find a horrible new environmental hazard?
No. Instead, they found the possible release of such materials from the kind of reactors used in United States nuclear power plants to be grossly overestimated. In fact, as Robert M. Bernero of the US Nuclear Regulatory Commission recently noted, the commission will probably propose relaxing what now seem to be overly stringent safety regulations sometime within the next year.
Did you know this? Probably not. It is common knowledge within the nuclear power industry. Yet, as far as the general public is concerned it may be one of the best-kept ''secrets'' of the day. News reporting tends to focus on the scary side of environmental issues, risks of nuclear power included. The TMI accident continues to be referred to as a near-environmental disaster, which it was not. Little or nothing is said in the news about the fact that it was far less dangerous, as far as release of radioactive material was concerned, than even official estimates of that risk had indicated.
Media treatment of nuclear power is only one example of a tendency to emphasize fear over fact. Risks of cancer associated with chemical pollution and food additives are cases in point. There are indeed serious environmental risks, especially from chemical pollution. But the widespread impression that environmentally related cancer rates are rising in the US is wrong.
Again, news reporting on the subject has emphasized fear and ill-informed speculation over the facts. Relatively little attention is given to expert analyses, such as those of the American Cancer Society, which show that US cancer rates (except those related to smoking) have generally remained stable or even slightly declined.
This is not to say that all such reporting is distorted or that there are not serious risks. But the Environmental Protection Agency administrator, William Ruckelshaus, identified the key element when he told the National Academy of Sciences last year: ''We are now in a troubled and emotional period for pollution control. Many communities are gripped by something approaching panic. And the public discussion is dominated by personalities rather than substance.'' Often such personalities are strident ''public interest'' advocates who play on public fear or frightened but ill-informed laymen. This biases reporting and makes it difficult to have a well-informed, productive public debate on the relevant issues.
Thus consumers of news should beware of reporting that tends to feed fear rather than reason. It will be interesting to see what kind of public debate erupts - and how well the issue is reported - when the US Nuclear Regulatory Commission tries to revise its safety regulations because present requirements are based on an overestimate of the risk of escape of radioactive materials.