A long simmering environmental concern is likely to boil up this summer. It's the possible health risks of ELF, the extremely low frequency electromagnetic fields emitted by power lines, industrial equipment, household appliances, and other such ubiquitous sources. A preliminary version of a United States Environmental Protection Agency (EPA) study that leaked out this spring suggested there may be a link between ELF and some childhood cancers. An official version of the report may be presented for public review anytime now.
When it does appear it is likely to stir public concern and bring the question of ELF safety to the fore. So it's worthwhile to take a quick look at what is and isn't known to keep this issue in perspective.
To begin with, the EPA did not carry out research itself but assessed work done by others. That assessment does not say a definite cause-effect link between ELF and childhood cancers is evident. It does say that there is enough suggestive evidence to warrant serious specific investigation. In other words, there's no cause for alarm. But there's also no cause for the complacency with which most scientists greeted questions about ELF safety until recently.
Indeed, the main significance of the EPA study is that it signifies that the possibility of ELF hazards is now getting serious attention.
Indira Nair, Granger Morgan, and Keith Florig of Carnegie-Mellon University put the issue in this perspective in a report they wrote last year for the congressional Office of Technology Assessment. They noted: ``As recently as a few years ago, scientists were making categorical statements that on the basis of all available evidence there are no health risks from human exposure to [ELF] fields. In our view, the emerging evidence no longer allows one to categorically assert that there are no risks. But it does not provide a basis for asserting that there is a significant risk [either].''
Much of the uncertainty lies in the subtlety of possible biological effects. ELF radiation is too weak and is not of the right frequency to heat up biological tissue the way microwave ovens cook meat. Some studies, however, indicate that there are effects at the level of molecular processes inside living cells. For example, Reba M. Goodman at Columbia University and Ann Henderson at City Universty of New York have found that ELF fields may stimulate activity of certain genes. This could, in turn, affect protein production in cells.
Last April, during the American Physical Society spring meeting in Washington, D.C., Thomas S. Tenforde, chief scientists for the Life Sciences Center of the Battelle Pacific Northwest Laboratory, reviewed ELF field interaction with humans. It's a subject where biology and radio physics meet. Dr. Tenforde explained that the surface of a living cell detects and amplifies ELF fields in ways that can alter synthesis of proteins within the cell. He called the effort to further understand this phenomenon ``a major challenge'' for ELF research.
According to the industry-supported Electric Power Research Institute, some $15 million a year now is being spent on ELF safety studies in about a dozen countries. Leonard Sagan, who heads the institute's own ELF research, says ``it is extremely important ... to continue vigorously pursuing the scientific and engineering questions'' involved to find out ``what, if anything, should be done.''
The EPA report, if and when it is officially released, should give added reason for this research, even though the findings are too tenuous to raise any clear alarm.