Wednesday, May 22, 2013
Covering Dallas, Monmouth, Independence, Falls City and surrounding areas since 1868
Radioactive radon gas can enter a home through pressure differences between the soil and foundation, and is the second-leading cause of lung cancer in the United States.
February 05, 2013
POLK COUNTY -- A significant percentage of homes tested for radon in Dallas and Monmouth have measurements of the radioactive gas that exceed federal health standards.
That's according to a recent analysis by Portland State University. In fact, a category of the test that examines short-term measurements showed more than 1 out of every 4 homes in Dallas is above what's considered a high-risk level by the Environmental Protection Agency.
Radon exposure is the second leading cause of lung cancer in the United States -- at more than 21,000 deaths a year -- after smoking, according to the Center for Disease Control.
"It's our intention to get people around the state to hear about this as they make decisions on health," said PSU geologist Scott Burns.
Burns worked with five of his students to compile radon test data from homes and businesses across Oregon -- about 33,000 in the Portland area, and 19,000 from the rest of the state.
"This is the first time we've been able to pull data from all 230 zip codes," said Burns, who's been tallying radon data for state health officials since the 1990s.
Radon is a naturally occurring radioactive gas formed by the breakdown of uranium in rock, soil and water. It's colorless, odorless and tasteless. The gas rises through soil and can be sucked into homes by pressure differences.
Once inside, the gas is trapped and can build to unsafe concentrations. EPA considers radon levels higher than 4 picocuries per liter -- the measurement used -- a health risk that should be mitigated.
"There's no escaping it," said Brett Sherry, radon program coordinator for the Oregon Public Health Department, adding that the air outdoors has an average radon concentration of .4 picocuries per liter.
Data used in Burns' study came from private homeowner tests in Oregon. Results were sent back to the state, then to Burns' team for analysis.
The Portland area has several neighborhoods with moderate- to high-risk radon levels because its soil contains granite, which has a high uranium content. A quarter of all tested homes were considered high risk, which is twice the national average.
Perhaps 1 out of every 15 tested homes in the rest of the state have a radon problem, though there are pockets of areas with moderate to high risk, such as the Silverton hills, Burns said.
Dallas had 104 homes tested, which makes for a solid sample size, Burns said. Long-term testings showed the percentage of homes with radon levels higher than 4 picocuries per liter was 16 percent -- which is considered moderate.
Short-term tests, meanwhile, showed high radon potential in Dallas, with almost 28 percent of homes having radon levels above the EPA safety standard.
Monmouth, which had 34 tests, showed a moderate risk in both categories of testing, though one long-term test was four times the EPA limit. Independence was a low-potential radon area, according to the study.
Burns said the hilly areas in Dallas contain marine sediment where higher radon values have been seen.
"The geology changes as you go from Dallas to Independence to tight, Missoula flood sediment," Burns said. "You don't have that level of permeability" in the low-lying ground.
The results of the PSU study aren't meant to be a cause for panic, Sherry said.
"But the message should be that every house should be tested," Sherry said.
"Don't rely on the maps to be the end all, be all."
* Radon test kits are sold at hardware stores or online. They utilize activated charcoal or chemically-enhanced plastic sheets for detection.
Cost of a short-term test kit -- which lasts from three to seven days -- is $10 to $15. A long-term kit -- 91 days to a year -- can cost $25. The kit is returned to the vendor after testing for processing and result evaluation.
* Mitigations can run from $500 to $2,000. Those typically involve using a pipe and ventilation system to bypass the general living space and move air outside the home where it can dissipate.
* Testing can have other positive effects beyond health. Burns said radon testing in a dwelling that shows levels below 4 picocuries per liter are considered a selling point for those trying to sell their home.
* For comprehensive radon information go to www.public.health.oregon.gov/HEALTHYENVIRONMENTS/RADIATIONPROTECTION and click on the "radon gas" link.