Better Plan, Wisconsin

SCIENTIST CHALLENGES THE CONVENTIONAL WISDOM THAT WHAT YOU CAN'T HEAR WON'T HURT YOU

SOURCE: National Institute on Deafness and Other Communication Disorders, National Institutes of Health,

July 28, 2010

A wind turbine is a rotary device with a gigantic propeller as big as a football field that turns in the wind to generate electricity. Although wind turbines are more often found in Europe than in the United States, they’re rapidly becoming more popular here as a “green” energy source. Most people consider that a good thing, except the rotors of wind turbines also generate noise, particularly in the infrasound range, that some people claim makes them feel sick.

Since frequencies that low can’t be heard, many scientists who study hearing have assumed they can’t have any effect on the function of the ear. But a little known phenomenon related to the infrasound generated by wind turbines is making some scientists challenge the common wisdom that what we can’t hear won’t hurt us.

Infrasound is a subset of sound broadly defined as any sound lower than 20 Hertz (Hz), which is the lowest pitch that most people can hear. It’s all around us, even though we might only be barely able to hear a lot of it. The whoosh of wind in the trees, the pounding of surf, and the deep rumble of thunder are natural sources of infrasound. Whales and other animals use infrasound calls to communicate across long distances. There is also a wide range of manmade infrasounds, for example, the noise generated by industrial machinery, traffic, and heating and cooling systems in buildings.

Alec Salt, Ph.D., is an NIDCD-supported researcher at Washington University in St. Louis who studies the inner ear. For years, he and his group have been using infrasound as a way to slowly displace the structures of the inner ear so that their movement can be observed. In their experiments, infrasound levels as low as 5Hz had an impact on the inner ears of guinea pigs.

“We were doing lots of work with low-frequency tones,” says Salt, “and we were getting big responses.” What they were observing in the lab, however, didn’t jibe with the scientific literature about hearing sensitivity, which was in general agreement that the human ear doesn’t respond to anything as low as 5Hz. Since human ears are even more sensitive to low frequencies than guinea pig ears, that didn’t make sense.

Salt and a colleague conducted a literature search, focusing not on papers about hearing sensitivity, but on the basic physiology of the inner ear and how it responds to low-frequency sounds. During the search, Salt found anecdotal reports of a group of symptoms commonly called “wind turbine syndrome” that affect people who live close to wind turbines.

“The biggest problem people complain about is lack of sleep,” says Salt, but they can also develop headaches, difficulty concentrating, irritability and fatigue, dizziness, and pain and pressure in the ear.

Continuing his search, Salt began to see a way in which infrasound could impact the function of the inner ear, by the differences in how inner ear cells respond to low frequencies. In function, our ear acts like a microphone, converting sound waves into electrical signals that are sent to the brain. It does this in the cochlea, the snail-shaped organ in the inner ear that contains two types of sensory cells, inner hair cells (IHCs) and outer hair cells (OHCs). Three rows of OHCs and one row of IHCs run the length of the cochlea. When OHCs are stimulated by sound, special proteins contract and expand within their walls to amplify the vibrations. These vibrations cause hairlike structures (called stereocilia) on the tips of the IHCs to ripple and bend. These movements are then translated into electrical signals that travel to the brain through nerve fibers and are interpreted as sound.

Only IHCs can transmit this sound signal to the brain. The OHCs act more like mediators between sound frequencies and the IHCs. This wouldn’t matter if the OHC behaved the same way for all frequencies—the IHCs would respond to what the OHC amplified—but they don’t. It turns out that OHCs are highly sensitive to infrasound, but when they encounter it, their proteins don’t flex their muscles like they do for sound frequencies in the acoustic range. Instead they actively work to prevent IHC movement so that the sound is not detected. So, while the brain may not hear the sound, the OHC responses to it could influence function of the inner ear and cause unfamiliar sensations in some people.

Salt and his colleagues still aren’t sure why some people are sensitive to infrasound and others aren’t. It could be the result of anatomical differences among individual ears, or it could be the result of underlying medical conditions in the ear that cause the OHCs to be ultrasensitive to infrasound.

Regardless, it might not be enough to place wind turbines further away from human populations to keep them from being bothersome, since infrasound has the ability to cover long distances with little dissipation. Instead, Salt suggests wind turbine manufacturers may be able to re-engineer the machines to minimize infrasound production. According to Salt, this wouldn’t be difficult. “Infrasound is a product of how close the rotor is to the pole,” he says, “which could be addressed by spacing the rotor further away.”

Salt, AN and Hullar, TE, “Responses of the ear to low frequency sounds, infrasound and wind turbines.” Hearing Research online 16 June 2010

COUNTY BOARD APPROVES WIND TURBINE ORDINANCE

SOURCE: Kewaunee County News, www.greenbaypressgazette.com

July 28 2010

By Kurt Rentmeester,

A week after the Kewaunee County Board approved a wind power resolution, some leaders question why it’s being done if a state Public Service Commission that sets such requirements is only weeks away.

In addition to new PSC requirements, Kewaunee County Supervisor Chuck Wagner said the county can’t regulate town zoning.

“The county rule is a recommendation. My problem is it’s all irrational hype. These people are making recommendations without having any significant data to back them up,” Wagner said.

The resolution addresses the same concerns that the towns of Carlton, West Kewaunee, Two Creeks, Mishicot and Two Rivers approved last month, as they are part of a proposed area for 111 wind turbines established by Oregon-based Element Power.

Wagner suggested tabling the resolution until July 18, but the board adopted the resolution on a 17-3 vote, with support from County Supervisors Jim Abrahamson and Bruce Heidmann. County Supervisor Jan Swoboda moved to adopt the resolution and Donald Delebreau seconded it.

“My intention was to give the support to town of Carlton and I felt there was no reason we don’t support other communities,” Swoboda said. “The PSC obviously will do what they think is best for the state.”

County Supervisor Linda Sinkula supported the measure in a Health Board resolution July 13 before bringing it to the board.

“At least it’s letting our legislators know there’s a concern and that we’d just like them to look at this,” Sinkula said. “We’d like them to look at the PSC rulings before they’re approved.”

Wagner said supporters have not investigated where the state and the municipalities are on these issues. He also said the state comment period is over and the state Legislature this year will not be back in session.

Supervisor Bruce Heidman said the measure needed to be rewritten.

“It was poorly written. That was my main problem with it,” Heidmann said. “There’s was nothing specific about the setbacks and other aspects of the resolution.”

County Supervisor Jim Barlow said the county needed to act on the resolution to make its case to state legislators.

“In part, if the PSC is going to have a ruling by the end of August, we can’t wait because they’re going to have something by the end of the month,” Barlow said. “We need to do what we can. Unfortunately, all we can do is end a resolution expressing some of our wishes.”

Residents speak

Andy Knipp, a town of West Kewaunee resident, said his greatest concern about wind turbines involve is the health impact on residents and on land values.

“Before anyone allows this to be built, the residents want to know what impact it will have on property values,” Knipp said.

Tina Steffen, a town of West Kewaunee resident, asked the county board to fight on her behalf to establish a policy to protect residents from the impact of wind turbine expansion.

“We have a Smart Growth Plan in the township,” Steffen said. “I’m not allowed to put a 50-story building up. These towers are 50 stories high and they’d be going up in an agricultural zone.”

Mike Paral of Kewaunee said costs for renewable energy were handed down from Madison, but local governments are nearly broke. The state can’t use taxes anymore, he said.

“Now I’m not against wind power,” Paral said. “You can have all the wind power you want — where it belongs. There are a lot of areas in the United States that have wide-open areas that have a thousand of these. Wisconsin is not one of them, much less Kewaunee.”

SECOND FEATURE

Download the resolution from the Brown County board of health and human services by CLICKING HERE