New federal and state tests of drinking water in New Jersey have detected far higher levels of radium in public water supplies than ever found before.

Officials of the New Jersey Department of Environmental Protection estimate that 75 to 100 public water supplies in South Jersey probably will be found unsafe by federal standards. New federal data, expected to be released by December, show that radium levels are about 160 percent greater, on average, than was previously known.

"There is a risk present in the drinking water that we didn't know was there," said David Huber, head of the radiological division of the U.S. Environmental Protection Agency in Washington. "It is not an inconsequential risk."

Huber said the EPA would take the necessary action to alleviate the risk.

For now, since their drinking water studies are incomplete, state officials say they do not believe there is a need to make a recommendation to the public. They said they intend to notify within a month those water authorities that have radium problems and would require treatment of the water.

The higher levels of radiation were documented after scientists in South Jersey detected radium 224, an isotope that had never previously been found in drinking water.

That discovery led the federal government to begin testing water in 27 states, including Pennsylvania and Maryland, for radium 224. That study will be released early next year, according to EPA officials.

Barker Hamill, head of the safe water division of the DEP, said that because of radium 224, radiation in some public supplies measures as high as 50 picocuries per liter of water. The federal safe health standard for radiation is no more than 15 picocuries per liter.

Hamill said the state cannot identify the public drinking water systems with high levels of radiation until the DEP study is complete.

The radium was found in the Kirkwood-Cohansey Aquifer, a 17 trillion-gallon water supply that serves at least 1.2 million people in South Jersey and that furnishes water to public and private wells. Federal and state testing during this decade has revealed that the aquifer is contaminated with more than a dozen potentially dangerous pollutants.

Radium is known to cause bone cancer. When radium is ingested, the body thinks it is calcium and stores it in bones. It is especially dangerous to children, whose bone structure is still developing.

Radium 224 was first found in drinking water last year in Toms River, where there is a suspected cancer cluster. Further statewide studies for radium 224 found that scores of public supplies that had never before shown a radiation problem are now testing positive for radiation.

"We had a suspicion radium 224 was out there," the EPA's Huber said. "Because of the problems in New Jersey, now we know it's true."

Radium 224 is related to radium 226 and 228. Radium 224 has a half-life of only 3 days, which means it decays quickly. Until the Toms River emergency, the government would wait weeks or months before analyzing water samples. By then, radium 224 had dissipated. In Toms River, the water was tested immediately.

If people drink radium 224 within 3 days of its entering their water supply, the radioactive isotope will decay in their bones, posing the same health hazard as the other types of radium, according to federal scientists.

The U.S. Geological Survey is conducting its own tests for radium 224 in wells in South Jersey and will release its findings in about a month, according to district director Eric Evenson.

The survey, which is working with the EPA in the national radium study, found earlier this year that 33 percent of private wells tested in South Jersey contained unsafe levels of radium 226 and 228.

In conducting the new tests for radium 224, the state for the first time also learned that some public water supplies had higher than expected levels of radium 226 and 228.

Huber said that radium 224 appears to have the same health effects as radium 226 and 228.

According to the EPA, one in 10,000 adults who drinks radium-tainted water over a lifetime will develop fatal cancer. As the amount of radium increases, so does the risk factor, officials said. The fatality rate for children is still unknown, according to the EPA. There is no danger in bathing or washing clothes with radium tainted water, according to state officials. Radium, which occurs naturally, gets into the water through pollution from fertilizer and lime used on residential and agricultural land. When chemicals from the fertilizers seep into the aquifer, they help move radium deposits into the water, according to a study that the geologic survey released this year.

The newest tests show that for every picocurie of radium 226 and 228 found in the water, there are 1.6 picocuries of radium 224. The result is that radium appears more than one-and-a-half times as prevalent as previously thought.

Hamill, of the DEP, said the state is grappling with how to deal with the radium 224 problem. Radium can be removed from public water supplies by installing expensive treatment systems. The concern, Hamill said, is that the state would then be left with radioactive waste accumulated in the water filters.

Radiological experts at the DEP are studying ways to dispose of the radioactive wastes, Hamill said.

Public water systems may choose to blend the radium-tainted water with clean water from untainted wells. That solution, generally used in recent years, is less practical as radium levels rise.

Another option is to dig deeper wells. Deep wells are less likely to be polluted, but there is no guarantee that radium will not find its way in.

Because radium 224 was only recently detected in drinking water, the EPA has yet to set health standards. For now, radium 224 is measured under the standard for safe radiation in water.

Huber said the EPA was trying to set a standard quickly but that there was a complicated mix of factors.

"It is science, politics, legal [ issues ] , and the ability to measure that all come together to make a decision," he said.

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