Ancient groundwater in Jordan has been found to have 20 times the recommended level of radioactive materials, according to a report in the journal Environmental Science & Technology. It featured the findings of a team of scientists from Jordan, the Palestinian Authority, Israel and the United States led by Avner Vengosh, associate professor of earth and ocean sciences at the Nicholas School of the Environment at North Carolina's Duke University. "The combined activities of 228 radium and 226 radium - the two long-lived isotopes of radium - in the groundwater we tested are up to 2000 percent higher than international drinking standards," Vengosh said in a statement. The researchers told the NRG news Web site that the radioactivity posed no threat to Israel's water. Similar radioactive particles might be found in some highly salinated underground wells in the Negev, but the water is only used for agriculture and is first desalinated, which removes the radiation, they added. The research team tested water from the Disi aquifer in southern Jordan, which supplies some of the country's population. It also provides water for Saudi Arabia, where it is known as the Saq aquifer. Vengosh said it was possible to render the water fit for consumption by removing the naturally-occurring isotopes, but the process was expensive. "Making groundwater from the Disi aquifer and similar sandstone basins in the region safe for long-term human use will require a significant reduction of radionuclide levels," he said. Jordan announced two years ago that it planned to invest $600 million to bring Disi water north to the residents of Amman and other cities, but it now looks as if the project's cost has jumped. Health officials could reduce radioactivity to safe levels by diluting radium-rich water with low-radium water from other sources, Vengosh said, or by treating it through ion exchange, reverse osmosis desalination or lime softening. Each does a good job of removing radium, he noted, but each produces solid and liquid residues that would have to be handled and disposed of as low-level radioactive waste. The US Environmental Protection Agency (EPA) classifies radium as a Group-A carcinogenic material, which means exposure to it could cause cancer.