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laurenh468

Everyday Exposure - 0 views

people.chem.duke.edu/...exposure.html

Exposure

shared by laurenh468 on 03 Jun 14 - No Cached
  • Radioactive elements found in rock, soil, water, air, and in food from the earth make there way in our bodies when we drink water, breath air or eat foods which contain them. These naturally occurring radioisotopes such as carbon-14, potassium-40, thorium-223, uranium-238, polonium-218, and tritium(hydrogen-3) expose us to radiation from within our bodies.
  • Radioactivity in nature comes from two main sources, terrestrial and cosmic. Terrestrial radioisotopes are found on the earth that came into existence with the creation of the planet.
  • Terrestrial
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  • . In areas where surface rocks contain a high concentration of uranium, radon gas could enter a home through a crack in the foundation. A concern for homeowners is the possibility that radon gas could accumulate to dangerous levels. This is especially a problem during the winter months when windows and doors are tightly shut.
  • interaction of cosmic rays with the earth's upper atmophere. Cosmic rays permeate all of space and are composed of highly energized, positively charged particles as well as high energy photons.
  • Approaching the earth at near the speed of light, most cosmic rays are blocked by the earth's protective atmosphere and magnetic field. As a byproduct of the interaction between cosmic rays (i.e. particles) and the atmosphere, many radioactive isotopes are formed such as carbon-14.
  • Cosmic rays are also composed of high energy photons, and not all are prevented from reaching the earth's surface. It makes sense that the higher you are in altitude, the more you are exposed to cosmic radiation. In fact, the average amount of exposure to cosmic radiation that a person gets in the Unites States roughly doubles for every 6,000 foot increase in elevation.
  • lying can indeed add a few extra units of exposure to one's daily exposure. Of course, the amount of extra exposure you get depends on how high the plane flies and how long you are in the air.
  • Think about this : Estimate how much cosmic radiation that astronauts are exposed to during their flights. Recall that astronauts fly at heights of about 160 miles
  • The human production of tobacco products introduces another way for us to get exposure to radiation. Smokers recieve a dose of radiation from polonium-210 which is naturally present in tobacco. Smokers also recieve an additional dose of radiation from the decay product of radon gas, polonium-218. Polonium-218 clings to aerosols such as tobacco smoke, and eventually winds up in the lungs. Once in the lungs, polonium decays by alpha particle emission and in the process may damage cells.
  • For examples, the bricks, stones, cements and drywalls that we use for the building of our homes, schools, offices frequently contain uranium ores and are thus sources of radon.
  • This exposure results from the attempt to diagnose fractures or cavities using x-rays, or to diagnose or treat cancer using injected radioisotopes. Patients are exposed to nuclear radiation in the diagnosis and treatment of cancer. Additionally, radiologists routinely use radioisotopes of technetium or thorium to diagnose heart disease.
  • These higher risk occupations include underground miners, radiologists, medical technologists, nuclear plant operators, research scientists and pilots.
  • Any amount of radiation can be dangerous because of the potential effect that it has on living cells. Radiation can disrupt normal chemical processes of the cells, causing them to grow abnormally or to die. Cells that are altered by the radiation may go on to produce more abnormal cells - a process that could eventually lead to cancer. At low doses, such as have been described here, cells are able to repair any damage rapidly. Any cells that die due to exposure can be replaced by the body. If one receives a very high dose, unlike any exposure mentioned here, the cells may not be able to be replaced fast enough and tissues or organs may fail to function properly.
laurenh468

NRC: Measuring Radiation - 0 views

www.nrc.gov/...measuring-radiation.html

Exposure

shared by laurenh468 on 08 Jun 14 - No Cached
  • Dose equivalent (or effective dose) combines the amount of radiation absorbed and the medical effects of that type of radiation. For beta and gamma radiation, the dose equivalent is the same as the absorbed dose. By contrast, the dose equivalent is larger than the absorbed dose for alpha and neutron radiation, because these types of radiation are more damaging to the human body. Units for dose equivalent are the roentgen equivalent man (rem) and sievert (Sv), and biological dose equivalents are commonly measured in 1/1000th of a rem (known as a millirem or mrem).
  • Exposure describes the amount of radiation traveling through the air. Many radiation monitors measure exposure. The units for exposure are the roentgen (R) and coulomb/kilogram (C/kg). Absorbed dose describes the amount of radiation absorbed by an object or person (that is, the amount of energy that radioactive sources deposit in materials through which they pass). The units for absorbed dose are the radiation absorbed dose (rad) and gray (Gy).
  • Radioactivity refers to the amount of ionizing radiation released by a material. Whether it emits alpha or beta particles, gamma rays, x-rays, or neutrons, a quantity of radioactive material is expressed in terms of its radioactivity (or simply its activity), which represents how many atoms in the material decay in a given time period. The units of measure for radioactivity are the curie (Ci) and becquerel (Bq).
laurenh468

ANS / Public Information / Resources / Radiation Dose Chart - 0 views

www.ans.org/...dosechart

Exposure

shared by laurenh468 on 09 Jun 14 - No Cached
  • The average dose per person from all sources is about 620 mrems per year. It is not, however, uncommon for any of us to receive less or more than that in a given year (largely due to medical procedures we may undergo). International Standards allow exposure to as much as 5,000 mrems a year for those who work with and around radioactive material.
laurenh468

Cellular Phones - 0 views

www.cancer.org/...cellular-phones

Exposure

shared by laurenh468 on 04 Jun 14 - No Cached
  • As noted above, the RF waves given off by cell phones don't have enough energy to damage DNA directly or to heat body tissues. Because of this, many scientists believe that cell phones aren't able to cause cancer. Most studies done in the lab have supported this theory, finding that RF waves do not cause DNA damage.
  • Some scientists have reported that the RF waves from cell phones produce effects in human cells (in lab dishes) that might possibly help tumors grow. However, several studies in rats and mice have looked at whether RF energy might promote the development of tumors caused by other known carcinogens (cancer-causing agents). These studies did not find evidence of tumor promotion.
  • Cell phones work by sending signals to (and receiving them from) nearby cell towers (base stations) using RF waves. This is a form of electromagnetic energy that falls between FM radio waves and microwaves. Like FM radio waves, microwaves, visible light, and heat, RF waves are a form of non-ionizing radiation. They don't have enough energy to cause cancer by directly damaging the DNA inside cells. RF waves are different from stronger (ionizing) types of radiation such as x-rays, gamma rays, and ultraviolet (UV) light, which can break the chemical bonds in DNA. At very high levels, RF waves can heat up body tissues. (This is the basis for how microwave ovens work.) But the levels of energy given off by cell phones are much lower, and are not enough to raise temperatures in the body.
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  • According to the Food and Drug Administration (FDA), which regulates the safety of radiation-emitting devices such as cell phones in the United States: "The majority of studies published have failed to show an association between exposure to radiofrequency from a cell phone and health problems."
  • According to the Federal Communications Commission (FCC): "There is no scientific evidence that proves that wireless phone usage can lead to cancer or a variety of other problems, including headaches, dizziness or memory loss. However, organizations in the United States and overseas are sponsoring research and investigating claims of possible health effects related to the use of wireless telephones." According to the Centers for Disease Control and Prevention (CDC): "Some… studies have suggested the possibility that long-term, high cell phone use may be linked to certain types of brain cancer. These studies do not establish this link definitively. Scientists will need to conduct more studies to learn more about this possible risk."  According to the National Institute of Environmental Health Sciences (NIEHS), which is currently conducting studies of the possible health effects of cell phones: "The weight of the current scientific evidence has not conclusively linked cell phones with any adverse health problems, but more research is needed." According to the National Cancer Institute (NCI): "Studies thus far have not shown a consistent link between cell phone use and cancers of the brain, nerves, or other tissues of the head or neck. More research is needed because cell phone technology and how people use cell phones have been changing rapidly."
laurenh468

Radiation sickness Symptoms - Diseases and Conditions - Mayo Clinic - 0 views

www.mayoclinic.org/...con-20022901

Exposure

shared by laurenh468 on 04 Jun 14 - No Cached
  • The severity of signs and symptoms of radiation sickness depends on how much radiation you've absorbed. How much you absorb depends on the strength of the radiated energy and the distance between you and the source of radiation.
  • The absorbed dose of radiation is measured in a unit called a gray (Gy). Diagnostic tests that use radiation, such as an X-ray, result in a small dose of radiation — typically well below 0.1 Gy, focused on a few organs or small amount of tissue. Signs and symptoms of radiation sickness usually appear when the entire body receives an absorbed dose of at least 1 Gy. Doses greater than 6 Gy to the whole body are generally not treatable and usually lead to death within two days to two weeks, depending on the dose and duration of the exposure.
laurenh468

Understanding Radon - Home Inspections by The Fulmer Group - 0 views

www.fulmerhomeinspections.com/understanding-radon.html

Exposure

shared by laurenh468 on 03 Jun 14 - No Cached
  • A Radon professional can evaluate your home and install a radon mitigation system. 
  • Radon is measured in terms of picocuries per liter of air (pCi/L). The estimated average radon level for indoor air is 1.3 pCi/L and 0.4 pCi/L for outdoor air.The current EPA guideline is to have the indoor air measure lower than 4 pCi/L.
  • Radon is generally tested by means of a radon monitor placed in the lowest livable level of the house, generally the basement.
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