Radiation and Human Beings
A study commissioned by Tehelka newspaper found that four-fifths of the Capital’s area is exposed to “unsafe” radiation levels. While this is genuine cause for concern, such radiation only constitutes the tip of the proverbial iceberg. Far more dangerous radiation sources surround us night and day: bricks, and other building materials. Radiation and cell phone radiation: the picture There are two types or radiation: (1) ionizing which knocks electrons from atoms producing ions, ex. x-rays, and (2) nonionizing, which usually does not dislodge the electron and is considered not as hazardous as ionizing radiation, for it only heats the surface layers of its target. The radiation from mobile phones and cell towers is believed to be of the second, less harmful kind. Tests on animals showed no harmful effects of radiation from cell phones. WHO in 2005 based upon the consensus view of the scientific and medical communities, stated that cancer is unlikely to be caused by cellular phones or their base stations and that reviews have found no convincing evidence for other health effects. European Commission in 2009 echoed that exposure to radio frequency fields is unlikely to lead to an increase in cancer in humans. Studies in other countries like Britain, Germany, Swedan shows similar findings. There is however another problem. The heat created by impinging radiation can indeed damage cells by overheating them. Since radio waves from a mobile telephone handset are absorbed by the part of the body adjacent to the phone, this causes heating of the tissue. While normal blood flow easily takes care of small amounts of heat, there is concern that prolonged use could cause headaches, fatigue, tissue swelling, tingling and, potentially, long-term damages. The bigger worry: ionizing radiation A greater worry is the ionizing radiation which is constantly present in the environment and is emitted from a variety of natural and artificial sources. This is called background radiation and one of its primary contributions is from the atmosphere, in form of radon gas which is released from the Earth's crust and subsequently decays into radioactive atoms that become attached to airborne dust and particulates. Other radioactive materials such as thorium are present in significant amounts in many sorts of rocks, other building materials and in the soil. Listed below are a few of common building materials and their estimated levels of uranium, thorium and potassium.
Other sources of ionizing radiation Other natural and man-made sources of this ionizing radiation are
Naturally occurring sources are responsible for the vast majority of radiation exposure. About 3% of background radiation comes from man-made sources such as:
Damage ionizing radiation can cause
The body has repair mechanisms against damage induced by radiation as
well as by chemical carcinogens. Consequently, biological effects of
radiation on living cells may result in three outcomes: (1) injured or
damaged cells repair themselves, resulting in no residual damage; (2)
cells die, much like millions of body cells do every day, being replaced
through normal biological processes; or (3) cells incorrectly repair
themselves resulting in a biophysical change.
The degree of damage caused by radiation depends on many factors - dose, dose rate, type of radiation, the part of the body exposed, age and health. Some of the symptoms of radiation sickness -- the result of extreme exposure, as for instance faced by atom bomb victims -- include actual burns to the skin, nausea, vomiting, and diarrhea, and can cause death.
Radiation and Cancer The correlations between radiation exposure and the development of cancer are mostly based on populations exposed to relatively high levels of ionizing radiation (e.g., Japanese atomic bomb survivors, and recipients of selected diagnostic or therapeutic medical procedures). Cancers associated with high dose exposure (greater than 50,000 mrem) include leukemia, breast, bladder, colon, liver, lung, esophagus, ovarian, multiple myeloma, and stomach cancers. The US Department of Health and Human Services literature also suggests a possible association between ionizing radiation exposure and prostate, nasal cavity/sinuses, pharyngeal and laryngeal, and pancreatic cancer.
Although radiation may cause cancers at high doses and high dose rates, currently there are no data to unequivocally establish the occurrence of cancer following exposure to low doses and dose rates -- below about 10,000 mrem (100 mSv). Those people living in areas having high levels of background radiation -- above 1,000 mrem (10 mSv) per year-- such as Denver, Colorado have shown no adverse biological effects. How to reduce ionizing radiation?
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