Doctors find no harm in widening ozone hole

May 14, 1993|By Jonathan Bor | Jonathan Bor,Staff Writer

Scientists who traveled to a wind-swept outpost near the southern tip of Chile said yesterday they could find no truth to reports that the expanding ozone hole had caused sheep to go blind and people to develop scorching sunburn and eye ailments.

But the team, led by Dr. Oliver Schein of the Johns Hopkins Wilmer Eye Institute, called for long-term studies to see if the ozone hole could be linked to chronic illnesses such as skin cancer and cataracts. Such studies would take 10 to 20 years.

Scientists made the journey last November to investigate reports of weird illnesses that followed a sudden expansion of the ozone hole, which normally covers Antarctica but no territory in South America.

In September and October of 1991 -- springtime in the Southern Hemisphere -- the ozone hole briefly grew to encompass southern Chile and Argentina, including the busy industrial port of Punta Arenas.

Farmers reported scores of sheep that suddenly went blind, and wild rabbits that had such trouble seeing that they could be approached and picked up. Meanwhile, in a land where the sun's rays normally slant through a thick cloud cover, people were complaining of intense sunburns, rashes and eye problems.

"I think that there are a lot of natural occurrences that always happen, things like diseases in cattle, epidemics and good years and bad years for harvests," Dr. Schein said. "I think it's very natural for people to look for explanations."

The ozone hole grew again around the same time in 1992. Reports of illnesses aroused concerns because they seemed a possible prelude to the effects that many environmentalists fear could follow a worldwide thinning of the ozone layer.

A thin band in the earth's upper atmosphere, the ozone layer filters most of the sun's ultraviolet rays. Alarm over ozone depletion has prompted many nations to phase out the use of chlorine-based gases in refrigeration and home insulation that are largely responsible for the problem.

But many scientists -- even some ardent environmentalists -- viewed the Chilean reports with skepticism. They said it was doubtful that a brief expansion of the ozone hole, lasting just a stretch of days in September and October, could cause widespread health problems in animals and people.

Eye and skin specialists from Johns Hopkins studied medical records kept by the doctors in Punta Arenas. They examined 24 fishermen and 21 shepherds, chosen because of their regular exposure to the sunlight, and 36 hospital workers, selected because they spend most of their time indoors.

Meanwhile, Dr. Kirk Gelatt, a Florida veterinarian, examined 250 sheep, 30 cattle and 20 rabbits.

In humans, the group did not find any notable increase in eye or skin conditions that are normally caused by exposure to the sun. In the animal groups, Dr. Gelatt saw some lambs with inward-rolling eyelids, but none was blind.

The rabbits looked healthy.

Scientists did find a slow-spreading skin cancer in young cattle, an intriguing finding because the disease usually strikes older cattle. Because the condition is often caused by ultraviolet radiation, Dr. Schein recommended that it be tracked in a long-term study.

The team, funded by the Environmental Protection Agency, suggested that the agency fund a longer investigation that would track skin cancers, precancerous skin conditions, cataracts and abnormalities of the immune system.

Although the ozone hole caused a doubling of ultraviolet radiation for several days in 1991 and 1992, the increase was less than 1 percent when spread out over a year's time.

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