Hauries d´instal.lar el plug-in del flash... Descarregar plug-in de Flash

Science for presidents

science for presidents

Health

Disminuir Aumentar

The health risks of radiation

The Japan’s recent nuclear incident has aroused fears of the invisible threat of radioactivity. But what are the harms of radioactivity on human health? Most of them are seen in the medium to long term and result in an increased risk of thyroid cancer, leukemia and other tumors

GONZALO CASINO | MARCH 24TH, 2011


Radioactive substances are characterized by their unstable molecules that continually disintegrate and upon exploding emit ionizing radiation and large amounts of energy. This energy is used in nuclear power plants to produce electricity, but it is extremely dangerous if it comes into contact with the human body. Ionizing radiation can be visualized as successive waves of small bombs exploding.

If these invisible explosions occur inside the human body, after radioactive particles have been inhaled or ingested through contaminated food, they cause severe cellular damage. The consequences can be catastrophic if they affect genetic material or irreversibly damage the cellular machinery. But the danger of radioactivity, like any poison, depends on the dosage.

Everyone is exposed to ionizing radiation (with sufficient energy to ionize matter, i.e. to produce ions) from natural sources such as cosmic radiation and the ground, or during routine medical tests like having an X-ray. Radioactivity is, therefore, present in our everyday lives: in the environment, air, plants (tobacco, for example, accumulates radioactivity) and in our homes.

Radon at home

Three quarters of natural radioactivity come from radon gas emanating from the ground (from the decay of uranium it contains). This varies greatly by geographical area (some places have 200 times more radon than others). In any case, natural radioactivity does not usually have significant health effects. In contrast, artificial radiation, like that generated in a nuclear plant, can be very dangerous or fatal if there is an accident or radiation leak.

In the case of the nuclear accident at Chernobyl in April 1986, the worst in history, 31 people died, hundreds were seriously contaminated and another 135,000 were evacuated, forced to flee their homes and all their belongings forever. Although some studies have documented an increase in cancers in the exposed population, the accident’s long-term consequences are still poorly understood (radiation may affect several generations).

Radioactive particles enter the body through their inhalation or contaminated food and waterExposure to ionizing radiation has, at first, an acute effect as a result of cellular damage produced by particles or waves of energy from the radioactive source. However, more worrying in terms of public health are its chronic effects due to their inhalation or ingestion through radioactive materials. Radioactive particles are dispersed in the air and can penetrate the lungs, contaminate all types of objects, soil and water, and eventually enter the food chain.

Genetic alterations

The main risk of radioactive particles is their effect on human DNA. Once in the body, they can alter the production of proteins and may facilitate the development of cancer. Among the survivors of the Hiroshima and Nagasaki atomic bombs from World War II, an increased risk of leukemia and other cancers was observed more than 10 years after the bombs were dropped.

Radioactive iodine (I-131), one of the main isotopes generated by nuclear fission, accumulates in the thyroid gland, increasing the risk of cancer. This gland uses iodine to produce thyroid hormones, so in the case of radioactive exposure it is recommended to take potassium iodide tablets to saturate the thyroid and thus preventing radioactive iodine capture. The risk of developing thyroid cancer is higher in children and adolescents. Cesium-137 is another dangerous radioactive isotope that damage cells, especially DNA, increasing the risk of different malignancies.

In the accident at the Fukushima nuclear power plant, which occurred as a result of the earthquake that hit Japan on March 11, 2011, there were leaks of radioactive particles. A few days later, the International Atomic Energy Agency (IAEA), found that in many parts of Japan elevated levels of radioactive isotopes of iodine-131 and cesium-137 had been detected in soil and water. But we have yet to see the extent of environmental damage and its effects on human health.

EFFECTS BY DOSE
The unit of measurement of received radiation is the sievert (Sv). On average, a person receives an annual dose of 3.0 millisieverts (mSv), 80% of which come from natural sources while the remaining 20% comes from artificial ones. Thus, a chest radiograph implies a dose of 0.1 mSv (equivalent to 10 days of natural radiation), a mammogram is 0.4 mSv (equivalent to 7 weeks), and abdominal CT scans, 15 mSv (5 years). The effects of ionizing radiation depend on the dose, exposure time (acute exposure is more dangerous than the same long-term dose) and other factors. In the short term, daily doses of 0.25 Sv will cause nausea and vomiting, while 1 Sv will cause redness of the skin, hair loss and burns. With daily doses greater than 3 Sv there is bleeding, diarrhea, peeling and sterility, and doses of more than 10 Sv prove fatal.

Comments

       
3 comments

jose luis 26/04/2012
Me hicieron pasar el scaner (con intravenosa en el brazo drcho) por el torax y noto dolores en la base de la columna y las lumbares¿como puedo contrarestar la radiación recibida? Gracias.

halima 28/11/2011
com els podem protegir de cada un dels radioactivitat

Juan Soriano Freire 31/03/2011
El ser humano para encontrar mejores formas de vida se inventa cada cosa,sin tomar en cuenta las graves consecuencia que pueden causar estas,en caso de accidentes. Que estamos esperando mas accidentes,mas consecuencias graves.Me pregunto si los beneficios momentáneos , están sobre la condición humana y su vida sobre la tierra. Somos seres inteligentes y podemos vivir mejor,pero no a este precio.

<< 1 >> 
 
Global Global Global Global
RSS