Wednesday, 24 October 2012

BE CAREFUL ABOUT RADON

"Radon is a colorless, odorless, radioactive gas. It forms naturally from the decay of radioactive elements, such as uranium, which are found at different levels in soil and rock throughout the world. Radon gas in the soil and rock can move into the air and into ground water and surface water.

Radon is present outdoors and indoors. It is normally found at very low levels in outdoor air and in drinking water from rivers and lakes. It can be found at higher levels in the air in houses and other buildings, as well as in water from underground sources, such as well water.


For both adults and children, most exposure to radon comes from being indoors in homes, commercial buildings, schools, and other places. The levels of radon in homes and other buildings depend on the characteristics of the rock and soil in the area. As a result, radon levels vary greatly in different parts of the United States, even within neighborhoods. Elevated radon levels have been found in every state.
The radon gas given off by soil or rock can enter buildings through cracks in floors or walls; construction joints; or gaps in foundations around pipes, wires, or pumps. Radon levels are usually highest in the basement or crawl space. This level is closest to the soil or rock that is the source of the radon. Therefore, people who spend much of their time in basement rooms at home or at work have a greater risk for being exposed.
Small amounts of radon can also be released from the water supply into the air, especially if the water source is underground. As the radon moves from the water to air, it can be inhaled. Water that comes from deep, underground wells in rock may have higher levels of radon, whereas surface water (drawn from lakes or rivers) usually has very low radon levels. For the most part, water does not contribute much to overall exposure to radon.
Radon exposure can also occur from some building materials if they are made from radon-containing substances. Almost any building material made from natural substances, including concrete and wallboard, may give off some level of radon. In most cases these levels are very low, but in a few instances these materials may contribute significantly to radon exposure.
Some granite countertops may expose people to different levels of radon. Most health and radiation experts agree that while a small portion of granite countertops may give off increased levels of radon, most countertops give off extremely low levels. People concerned about radon from countertops and from other household sources can test these levels using home detection kits or by hiring a professional to do the testing


Long-term exposure to radon can lead to lung cancer. Radon in the air breaks down quickly, giving off tiny radioactive particles (radon progeny). When inhaled, these particles can lodge in the lining of the lungs, where they can damage the cells there. This may eventually lead to lung cancer.
Cigarette smoking is by far the most common cause of lung cancer in the United States, but radon is the second leading cause. Scientists estimate that about 20,000 lung cancer deaths per year are related to radon.
Exposure to the combination of radon gas and cigarette smoke creates a greater risk for lung cancer than either factor alone. Most radon-related lung cancers occur among smokers. However, radon is also thought to cause a significant number of lung cancer deaths among non-smokers in the United States each year.
Some studies have suggested that radon exposure may be linked to other types of cancer as well. But the evidence for such links has been inconsistent and not nearly as strong as it is for lung cancer. Because radon and its progeny are absorbed mainly by inhaling, and because the alpha particles they give off travel only a short distance, it is unlikely they would affect other tissues in the body.
The evidence that radon causes lung cancer comes from studies in people and studies done in the lab.", in www.cancer.org

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ATENÇÃO AO RADÃO


"Alina Louro lidera um estudo sobre a concentração de gás radão nas habitações e os efeitos que poderá ter para a saúde humana, que está a ser realizado na região da Guarda.
Segundo a responsável, que é docente na Escola Secundária Afonso de Albuquerque (ESAA), naquela cidade, o radão é um gás radioactivo presente nos solos, no ar e na água e, quando em concentrações elevadas, pode constituir-se em factor de risco ambiental.
Explicou que “o radão é um gás natural (…), é um gás nobre e existe no ar” que “está associado aos granitos e à existência de rochas de origem granítica, que são ricas em cristais de urânio e outros átomos que são abundantes neste tipo de rocha”.
“Nós inalamos radão quando respiramos”, referiu, indicando que a Organização Mundial de Saúde “aponta o radão como a segunda causa de morte por neoplasia pulmonar”.
Contudo, observou que importa saber “quais são as concentrações para que isso possa acontecer, para ele poder condicionar um problema desse tipo”, contributo que poderá ser dado pelo estudo em curso na Guarda, que envolve a Universidade da Beira Interior, o Laboratório de Radioactividade Natural (Coimbra), o Hospital e a Câmara da Guarda.
O radão é um gás radioactivo que não tem cor, sabor nem cheiro, não reage quimicamente e por isso não é detectável pelos sentidos e após a libertação do solo vai alojar-se no interior das habitações, segundo fonte do projecto.
Com o “Projecto SOS Radão Guarda” os responsáveis pretendem conhecer as concentrações médias de radão nas habitações, elaborar um mapa de risco, conhecer as concentrações nas águas e poços, minas e furos e solucionar problemas em habitações.
“Abra portas e janelas sempre que as condições atmosféricas o permitem”, é o repto lançado aos habitantes da região.
Os promotores do projecto referem, num panfleto distribuído à população, que “as concentrações de radão decrescem muito numa habitação ventilada durante cinco horas”.", in  Destak/Lusa

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