Radon Gas
The collection of deadly radon gas is an environmental hazard associated with areas of karst topography. Radon gas is a known cause of lung cancer. Many areas with karst bedrock are composed of limestone. Phosphate minerals that occur naturally in limestone contain small amounts of uranium. Uranium is a radioactive, toxic element which is easily oxidized. As a result of the uranium degrading into lead, small amounts of radon are produced as a byproduct. Over a period of time, this radon gas can accumulate within solution-derived karst cavities or in naturally occuring joints in the bedrock.
Joints in limestone bedrock that allow for crevasses and cavities to form through solution processes.
http://www.unomaha.edu/geomorf/Jessica/intro.html
Structures built above karst cavities are prone to infiltration of radon due to fluctuations in atmospheric pressure (Ruthven, C. et. el., 2002). Also, it is believed that considerable amounts of radon are produced with in the soils overlying karst bedrock. This radon is thought to be released into water reservoirs beneath the surface following heavy rain events (Savoy, L. et el,)
Household radon gas infiltration sources from areas of karst bedrock
Household radon test kits are readily available and fairly inexpensive. They are easy to use and the results are easy to evalute. Levels registering greater than 4.0 picocuries are cause for concearn. If you find yourself in this category, the EPA recommends actions be taken to improve the conditions within your residence such as allowing for more ventilation of basements and crawlspaces in the house, as well as sealing crawl spaces with plastic(http://www.gcrio.org/geo/karst.html, 2004). Also, these potential geologic hazards can be identified by geologists in order to mitigate the risks that are presented by the karst bedrock.
Radon infiltration is a problem to be taken seriously. Prolonged exposure to the gas can result in serious health problems and even death. If you believe you may have radon infiltration problems, here are some links that may help you:
Radon testing database, type in your zip code: http://www.servicemagic.com/task.Radon-Gas-Testing.40239.html;jsessionid=F0AE12D7B7EE1B9DA4606F94B8F9757D.worker1
Free radon testing kits through the EPA: - http://www.free-radon-test-kits.com/
