More questions in Jeffco tower study

Charley Able, Rocky Mountain News

Friday, September 22, 2006

A long-awaited study suggests living close to radio and television towers possibly could affect people's health, but does little to settle debate over whether a proposed tower should be built on Lookout Mountain.

The study, the first to examine the possible effects of radio frequency emissions, indicates a possible link between proximity of homes to radio and television broadcast devices and biological effects of radio frequency exposure, but one of its authors said many questions remain.

"Just like all good scientific research, more questions have been raised than answered," said James B. Burch of the University of South Carolina's Department of Epidemiology and Biostatistics.

"I don't know that we have the data to make the determination of just exactly what it means, or exactly what is going on, or whether it is significant or not," Burch said.

For years, opponents of proposals to place digital television broadcast transmitters on a tower atop Lookout Mountain have argued that the RF emissions from the towers are endangering the health of nearby residents.

That is disputed by supporters of broadcasters, who are under a federal mandate to provide free, over-the-airwaves high definition television broadcasts.

Lake Cedar Group, a consortium of four local television stations, wants to build a 730-foot broadcast tower to house the HDTV transmitters on a 65-acre site atop the mountain.

Three existing towers would be removed if the plan is approved.

The Lake Cedar application was approved by former Jefferson County commissioners in 2003, but it has been returned twice for further consideration by a district court judge.

Commissioners have not set a hearing date to respond to the latest court remand.

The study, conducted by Burch and other researchers at Colorado State University and the University of Washington in Seattle, measured the production of "markers" believed to play significant roles in the human immune system.

"A robust immune system is important for people who have cancer. It is thought that the immune system plays a role in tumor surveillance, detecting microscopic tumors, and eliminating them before they become cancerous growths," Burch said.

Previous studies by the Colorado Department of Health and Environment found increases in tumors among residents of two areas on Lookout Mountain, but found no conclusive link between the cancers and the broadcast towers.

The new study found the closer people live to the towers the higher their exposure to radio frequency emissions.

The study indicates changes in immune system markers such as white blood cells, lymphocytes and T-cells could be related to increased RF levels because the markers "were all significantly increased among persons" in the highest areas of exposure as compared with those in the areas of lowest RF exposure.

"The study shows there are biological effects that are associated with increased RF power densities within the homes," Burch said. "But what does an increase in immune markers mean? Those are difficult things to interpret."

The study indicates people with lower than normal levels of melatonin may be more susceptible to the effects of RF radiation, Burch said.

But he also said the results of the study could be "a spurious finding" or could mean there is a direct biological effect.

Melatonin regulates the sleep cycle and is associated with the performance of the human immune system.

The increased counts of white blood cells, lymphocytes and T-cells, which are a type of lymphocytes, usually signal viral infections, said Dr. Mark Johnson of the Jefferson County Department of Health and Environment.

The level of the increased markers found by the study is within the normal range of variance from person to person, Johnson said.

The study means any decision on the tower should be approached with caution, said Deb Carney, spokeswoman for Canyon Area Residents for the Environment.

"We are seeing warning signs. If you wait until it is absolutely 100 percent certain that it does something to us, then there has been a whole lot of harm done in the meantime," Carney said.

Marv Rockford, spokesman for the broadcaster's group, said the study furthers Lake Cedar's position that no link exists between the Lookout Mountain broadcast devices and health risks.

"I would support the statement that this has to be weighed against the vast body of research that has been done in this area, which . . . does not support the contention that there is any adverse impact on health from exposure to RF below the safety guidelines," Rockford said.