Are World’s Beaches Clean Enough for Swimming? : Check with local authorities before swimming in waters near cities or factories.

When Andy Palmer traveled to Rio de Janeiro this summer to attend the Earth Summit, the United Nations Conference on the Environment, he couldn’t forget the purpose of his trip even while relaxing on the beach. “People were constantly warning me not to swim,” recalled Palmer, political director of the American Oceans Campaign, a nonprofit environmental organization based in Washington, D.C.

The warnings, which came from Rio residents and not from scientists attending the summit, reflect a growing concern for a growing global problem. Beaches formerly considered world-class--beaches immortalized in movies and song--are now so polluted that simply swimming or wading in them can make us sick.

How widespread is the problem? No one can say for sure, especially on a global level, according to the half-dozen experts asked the question. Even worse for international tourists: No one can say with certainty how to eyeball a beach to determine if it is safe for swimming.

“Almost any beach near civilization in a developing country might be unsafe,” said Allen Hammond, editor-in-chief of “The 1992 Information Please Environmental Almanac.”

But U.S. beaches are nothing to brag about, either, as last week’s Southern California beach closings between Venice and Playa del Rey confirm. In 1991, there were more than 2,000 beach closures, according to the first national report on such closures released last month by the Natural Resources Defense Council, a national public interest environmental law firm. The closures stemmed from high levels of bacteria, primarily caused by discharges of human and animal waste, according to the NRDC report.

Most likely to be closed were beaches along the coastlines of New York, New Jersey and Connecticut, with 715 closures, and the Southern California coastline from Los Angeles to San Diego, with 588.

The worst of the bad? Imperial Beach in San Diego, at least in the view of Stephen Leatherman, director of the University of Maryland’s Laboratory for Coastal Research. Leatherman compiled a worst-five list of U.S. beaches recently for Travel Holiday magazine. In addition to Imperial Beach, the list includes Great Kills Beach on Staten Island, Coney Island Beach in Brooklyn, Sea Bright beach north of Asbury Park in New Jersey and Holly Beach near the Texas border in Louisiana.

“As bad as some of our beaches are, it is much worse overseas,” Leatherman said. “One of the worst is Porthcawl, near Cardiff in South Wales. Raw sewage goes out into the water.” Polish beaches are also on his “to-avoid” list.

Swimming in polluted waters can cause a variety of ailments, according to the federal Centers for Disease Control and the NRDC. Viruses are the main cause of swimming-related diseases, according to the NRDC, and most commonly result in gastroenteritis (an inflammation of the stomach and intestines). Gastroenteritis can also be caused by bacteRia such as salmonella, said Dr. Duc Vugia, medical epidemiologist with the Federal Centers for Disease Control. Symptoms include vomiting, nausea, diarrhea and fever.

Other dangers: Swimming in polluted ocean water can result in potentially life-threatening typhoid, a type of salmonella infection that requires immediate medical attention, Vugia said. Or swimmers can contract skin rashes and pinkeye, an inflammation of the transparent membrane covering the white of the eye. Less common is hepatitis A, an inflammation of the liver, Vugia said.

How do we actually contract such illnesses and infections?

“If you have an open wound, it might become infected with an organism,” said Vugia. Risk of contracting disease also increases, according to the CDC, if swimmers submerge their heads.

As the number of bacteria in the water rises, the incidence of illness increases, several studies have found. According to the July, 1992, NRDC report, one study found that as many as 58,000 illnesses a year among Hong Kong residents could be traced to swimming at a single beach.

Swimmers exposed to water-borne viruses often notice symptoms within a couple of days, said Vugia. “For bacteria (exposure) symptoms (to show up) might take a week,” he said.

Affected swimmers should seek medical attention, experts say, if symptoms such as vomiting or diarrhea are severe or if symptoms are accompanied by a fever. The outlook for recovery, said Vugia, is good if proper medical attention is obtained.

For tourists anxious about the possible effects of ocean pollution, there are a few ways to check out beach safety, although none is foolproof.

“Try to find a reliable local source,” advises Dr. Leonard Marcus, a travel medicine specialist in Newton, Mass., who recommends seeking out a local public health official, environmental group or a university researcher. “The 1992 Information Please Environmental Almanac” (Houghton Mifflin Co., $9.95 paper) contains discussion of water-pollution problems. In its entry for Portugal, for example, the guide notes that 70% of the country’s water pollution occurs in coastal areas.

Domestically, the NRDC is calling for the creation of a national beach protection program. Its aim would be to establish a uniform national water quality standard, a comprehensive monitoring and closure program and a public notification system whenever standards are violated.

Hammond is not optimistic that the global outlook will improve soon. “It takes billions to build sewage and water systems,” he said. Clean-up projects are costly, too. A five-year plan to clean up San Diego Bay, recently approved by the Unified Port District, is expected to cost as much as $126 million just to clean up nine so-called toxic hot spots of industrial pollutants.

Until then, Hammond’s advice is simple: “Pick your (swimming) sites carefully.”

Leatherman suggests confining your ocean swimming only to pristine places. In the United States, his top five choices are: Sanspur Beach in the Florida Keys, Grayton Beach State Recreation Area in Pensacola, Fla., East Hampton (Main Beach) on Long Island, Santa Barbara (East Beach) and Beverly Beach State Park near Newport, Ore.

And if Leatherman left the country in search of an unpolluted beach? “I’d head to Tahiti.”