MIDDLEBURY - In the months following the discovery of high amounts of naturally occurring radioactive elements in drinking water in and around the Chittenden County area, including one sample from Weybridge, geologist Jon Kim has been trying to peg where and how these elements are getting into the drinking water, and he's run into a snag.

Kim, who works with the Vermont Geological Survey, is butting heads with the state health department, which tests water samples for the radioactive elements, which include radium, radon and uranium. At a presentation to geology students at Middlebury College on Thursday, Kim said to specifically target danger zones he needs access to samples from both private and public wells. The health department is tight-lipped about private wells, however, because that information could lower property values if commonly known.

"The health department has been very reluctant to give out any information on private wells, and I can't blame them. Right now, I can only map the test results by zip code, and it's hard to make a correlation between the radiation levels and the rock formations," he said.

The issue at hand involves identifying the culprit responsible for the high levels of radiation. Initially, state geologists suspected that radioactive elements in the Clarendon Springs rock formation - which extends along the western edge of the state from Highgate Springs in the north to Bennington in the south - were responsible. But Kim is certain that the answer isn't as cut and dry. Numerous tests by geologists dating back as far as the 1950s have shown uranium-rich strips of bedrock running throughout the state. Those deposits, several of which have been found extending underneath the towns of Starksboro, Granville and Lincoln, can't be attributed to one formation, said Kim.

Currently, Kim and others are studying the likelihood that a combination of conditions are to blame, including fault lines and rock formation composition. Tests on wells in St. George and Monkton, which both yielded high amounts of radiation, came from different rock formations.

Studies of the water in the Monkton well - which yielded radiation levels that were 200 times as high as the acceptable level - were attributed to a fault line, which Kim suspects pushed the radioactive elements toward the surface as the earth shifted.

Kim said the elements can make a person sick if ingested over a long period of time. Cancer risks are very real, he said.

If people are concerned about the level of radioactive elements found in their water, they can send samples to the health department for testing, said Kim. But testing on private wells isn't required by the state, which could lead to people drinking contaminated water unknowingly, he added. To ensure people have an idea of the potential danger of being exposed to radioactive contaminants, Kim said access to water samples is that much more important.

"We're trying to develop the capacity to study the state's wells and rock formations," he said, "and we're just getting started. I think already we know what we're up against."