Radon: Geology Explains How the Gas is Released
What seems to be the problem with radon that the US. Surgeon General ranks it as the second leading cause of lung cancer? There are warnings about checking the radon levels in our homes, but the EPA has yet to offer explanations why this gas has proliferated in our midst to cause us terrible harm.
First-Off -- Understand Radium vs. Radon
Most homeowners or house-hunters are in search of facts about radon in order to understand its geology and why there are high levels of it. If you want to know where it comes from and what makes the existence of a noxious gas possible in a particular geological site, knowing the types of rocks in the said area helps in determining the degree of uranium present.
Radon is a by-product of uranium as it is released as part of the latter’s radioactive decay. However, the release of the radioactive gas depends on the reaction of yet another by-product known as radium. During the decaying processes, the latter ejects an alpha particle that will cause the radon atom to recoil in the opposite direction. In a mineral where the radium atom occupies a big grain, or if the alpha recoil produced is directed toward the inner core, the radon atom remains embedded deep in the grains.
Now if the decaying uranium produces a radium atom that causes the radon atoms to recoil toward the surface of the grain, then the noxious gas will exit and will be released into the Earth’s atmosphere.
However, before we go any further, radon is actually considered as a noble gas because of its stable characteristic, which denotes that it does not interfere or react with other gaseous forms. If found and used in its right element, this colorless and odorless gas has a noble use as a conductor of electricity. It can also give off illumination because it has the ability to emit electromagnetic radiation, especially when in contact with ultraviolet rays. Hence, many were attracted to its high potentials during the early days of its discovery.
The Geology of Uranium
Uranium is a mineral that is commonly present in all types of rocks and soil, but not all rocks have the same levels of uranium content. The smallest amount is measured at one to three parts per million (ppm). Rocks that have higher uranium content are the light or yellow colored volcanic rocks. They include the shale and metamorphic rocks that subsequently took form as a result of sedimentation in various igneous and hydrothermal conditions.
Rocks that have high levels of uranium contain as much as 100 ppm. It can be said then, that the higher the level of this ore mineral present in a geological site, the higher the levels of radium and radon that are present in this environment.
Uranium is described as an unconformity-related deposit. (The term unconformity refers to a surface that is separated into two layers.) It denotes that there is an initial layer where deposition, erosion and removal of sedimentation and rocks occurred, before a second wave of deposition took place to cover the land.
A uranium ore mineral possesses physical and chemical properties that can be extracted and used alone or with other metals. However, rocks are categorized into different types and are graded not according to their amount of uranium content but to its quality. A small amount of uranium may be present but if its composition is quite complex as to allow it to combine with other elements, then that rock is classified as a uranium ore mineral.
In some cases, if the uranium content in a rock is too difficult to extract, then that rock is not considered as high-grade nor regarded as a uranium ore-mineral. Apparently, the cost that will be incurred for extraction processes will not be met with useful and profitable uranium content. This is why some minerals containing as much as 50 percent uranium are not classified as ore minerals.
There are two known types of rocks that contain high-grade uranium. These are the “uraninite" and the “pitchblende". The latter is actually uraninite but occurring in massive varieties as they occur mostly where there is an abundance of primary uranium vein deposits. These high-grade uranium ores are found all over the globe; in the Eldorado mines of the Belgian Congo, in the Great Bear Lake of the Northwest Territories of Canada and in the mines of Joachimsthal, in Czechoslovakia.
In the United States, pitchblende ore minerals are found dispersed in the volcanic rock deposits of the Colorado Plateau and in the limestone deposit of Grants district of New Mexico.
The Occurrence of High Levels of Radon
As mentioned earlier, radon is a by-product of uranium through another atom known as radium. Since its emission depends on the alpha recoil of the radium atom, this gas most often occurs in controlled and low levels of concentration.
It is at this point that information about radon becomes baffling, since its geologic formation and release on the Earth's surface is mainly dependent on the radium isotopes and its alpha recoil.
What could have caused the widespread occurrence of radon, if not all rocks and soil in the U.S. have high levels or high-grade uranium content ?
The Disturbing Revelations at Port Hope, Ontario
It is said that quite a number of homes and schools in Port Hope, Ontario, were built with construction filling-materials derived from sand-like uranium tailings. These tailings are the massive quantities of pulverized rock produced from milling the ores, in order to extract uranium. In fact, it takes about a ton of ore in order to extract two pounds of uranium mineral.
Rather than let the pulverized rocks go to waste, the sand-like material became useful as construction fills for homes and schools, and this of course, had equated to great savings. Similar treatment for phosphate and other mine tailings were applied to construction work in Florida, Newfoundland and in some areas outside of Montreal. This was during the 1970s.
However, the radon element was overlooked, as the milling or pulverization process allowed the release of radon gas. Ordinarily, it should have been deeply embedded in the grains of the mineral due to the alpha recoil. Yet, all the milling processes that produced massive amounts of tailings had allowed the release of radon gas by at least 10,000 times the rate of the naturally formed radon.
In all the ores milled and pulverized, uranium was present in all deposits, both high and low levels--- therefore releasing radon gas in high amounts. St. Mary’s School in Port Hope was found to have extremely high radon levels, which subsequently led to the discovery that more than a hundred homes and gardens in the area had radon gas emissions, beyond the tolerable levels.
The Unraveling of the Manhattan Project
In fact, it is reported that the remedial actions to remove the uranium tailings, used as construction fills for the schools and the homes were made at the government’s expense. Now why should the government use public funds if this was some form of corporate infraction?
It was later revealed that it was part of El Dorado’s Manhattan Project, which was in collaboration with the U.S. government’s development of the first atomic bomb and it started during the 1930s. These were the very bombs used during the World War II attack against Japan.
The unraveling was in 1975, yet in 1990, it was disclosed that there are still 200,000 tons of radioactive debris in the ravines of Port Hope. During that time, El Dorado Nuclear Limited, the company who had donated the radioactive tailings was still being prodded by the Ontario Environmental Department to clean-up the mess.
A publication dated April 2011, reported that the citizens of Port Hope are said to be divided. Others are still hoping that the mess and the radioactive levels can still be cleaned-up while those who have lost hope are pushing for the relocation of the entire town. (Please find link for this news item in the Reference section of this article).
Delving into the geology of radon has brought us to another discovery of the harms brought about by nuclear energy. It appears that the atomic bomb that hit Hiroshima, Japan during the World War II events, likewise hit the U.S. on a wider scale and for a longer term.
To date, facts about radon include the EPA's estimates of about 21,000 lung cancer deaths caused by radon every year. The noble but harmful gas is said to be all over the U.S. and can be in buildings, homes, offices, schools and gardens. In fact, the EPA warns, that families are liable to get higher exposures by staying within the confines of their homes. Although Radon Zone Maps are provided by the federal agency, it would still be best to know not only the geology but also the history of your location.
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