U-M scientists studying the loss of stratospheric ozone, the rise in ground-level UV-B radiation, and the impact of UV-B on plants, animals and human health will have some new instruments in their tool kit this spring.
In April, the Biological Station in Pellston will join with nine other sites across the nation to take systematic
UV-B measurements using top-notch equipment provided by the United States Department of Agriculture.
Eventually, data from all the sites will be correlated with ecological data to determine the effects of UV-B on the ecosystemplants, animals and algae. Data from the U-M site also will be correlated with epidemiological data and human health studies.
Scientists know that UV-B radiation can trigger skin cancer, injure the human auto-immune system, and reduce the rate of photosynthesis in plants and algae. Indeed, in the early history of the earth when there was little ozone in the atmosphere, excessive UV-B rays prevented the development of life on land, says James Teeri, professor of biology and director of the Biological Station.
We suspect the amount of UV-B reaching the earth is increasing as CFCs (chlorofluorocarbons) chew into the ozone layer that shields the earth from UV-B. Unfortunately, accurate ground-level UV-B measurements have proved elusive, says Robert H. Gray, professor of environmental and industrial health at the School of Public Health. The new USDA equipment should help fill that gap.
The instruments at the Biological Station will be set in a five-acre clearing in a forest and exposed to the sky to within 10 degrees of the horizon. Three different UV-B monitoring instruments will gather data that will permit scientists to assess the effects of ground-level UV-B radiation.
One UV-B health experiment already under way is led by Kevin D. Cooper, associate professor of dermatology. Cooper has been measuring the impact of UV-B on disease-fighting lymphocytes in humans after exposure to a sun lamp or solar simulation lamp great enough to trigger a mild to moderate sunburn. Cooper expects to collect similar data on subjects at the UV-B measurement site in Pellston and coordinate it with UV-B radiation data.
In the future, we and scientists at the other sites hope to analyze epidemiological data from national and international agencies and registries and relate our findings on human health effects to
UV-B levels, Gray says.
This problem will be around for a long time, Teeri adds. In 1983, the ozone hole over the Antarctic was the size of the United States. In 1993, it was three times the size of the United States. Furthermore, if the release of CFCs ceased instantly, it would still take nearly 100 years for the ozone to recover.
While ozone depletion seems to be greatest in the Southern Hemisphere, recent studies in Canada suggest that ozone layers may be thinning in the Northern Hemisphere as well.
Teeri and Gray invite U-M faculty and students to submit UV-B research proposals to the Biological Station office. For information, call 763-4461.