question: How can be something contaminated by radiation?
comment: Well to start with your classic forms of radiation are alpha radiation (basically, helium nuclei), beta radiation (basically, ~~neutrons~~ edit: electrons/positrons) and gamma rays. But more importantly, "contaminated by radiation" generally means "contaminated with radioactive particles" rather than "zapped with gamma rays". Eg, it's got plutonium dust all over it, or something similar. If you have been contaminated with a substance like this, it will decay over time and irradiate you. The other form of "contaminated by radiation) means that you've gotten a dose of it radiation that transformed materials from nonradioactive elements and isotopes into radioactive ones.
passages: Irradiation is the use of ionising gamma rays emitted by cobalt-60 and caesium-137, or, high-energy electrons and X-rays to inactivate microbial pathogens, particularly in the food industry. Bacteria such as "Deinococcus radiodurans" are particularly resistant to radiation, but are not pathogenic. Active microbes, such as "Corynebacterium aquaticum", "Pseudomonas putida", "Comamonas acidovorans", "Gluconobacter cerinus", "Micrococcus diversus" and "Rhodococcus rhodochrous", have been retrieved from spent nuclear fuel storage pools at the Idaho National Engineering and Environmental Laboratory (INEEL). These microbes were again exposed to controlled doses of radiation. All the species survived weaker radiation doses with little damage, while only the gram-positive species survived much larger doses. The spores of gram-positive bacteria contain storage proteins that bind tightly to DNA, possibly acting as a protective barrier to radiation damage.
   Such contamination presents a hazard because of the radioactive decay of the contaminants, which produces such harmful effects as ionising radiation (namely α, β, and γ rays) and free neutrons. The degree of hazard is determined by the concentration of the contaminants, the energy of the radiation being emitted, the type of radiation, and the proximity of the contamination to organs of the body. It is important to be clear that the contamination gives rise to the radiation hazard, and the terms "radiation" and "contamination" are not interchangeable.
   In environments where nuclear safety and radiation protection are required, radioactive contamination is a concern. Radioactive substances can appear on surfaces, or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable, and processes can give rise to their presence in such places. Several examples of radioactive contamination include:
  
  BULLET::::- residual radioactive material remaining at a site after the completion of decommissioning of a site where there was a nuclear reactor, such as a power plant, experimental reactor, isotope reactor or a nuclear powered ship or submarine
   BULLET::::- As already mentioned, radiation can have a toxic effect on organisms.
  
  Section::::Measuring.
   Section::::Health effects of contamination.:Biological effects.:Internal irradiation.
  
  Radioactive contamination can be ingested into the human body if it is airborne or is taken in as contamination of food or drink, and will irradiate the body internally. The art and science of assessing internally generated radiation dose is Internal dosimetry.
   BULLET::::- European Committee on Radiation Risk (ECRR) the stage of radiation depends on the stage the body parts are affected
  
  Section::::Exposure pathways.
  
  Section::::Exposure pathways.:External.
  
  External exposure is exposure which occurs when the radioactive source (or other radiation source) is outside (and remains outside) the organism which is exposed. Examples of external exposure include:
  
  BULLET::::- A person who places a sealed radioactive source in his pocket
  
  BULLET::::- A space traveller who is irradiated by cosmic rays
   Surface contamination may either be fixed or "free". In the case of fixed contamination, the radioactive material cannot by definition be spread, but its radiation is still measurable. In the case of free contamination there is the hazard of contamination spread to other surfaces such as skin or clothing, or entrainment in the air. A concrete surface contaminated by radioactivity can be shaved to a specific depth, removing the contaminated material for disposal.
   BULLET::::- A person who is being treated for cancer by means of a radiopharmaceutical where a radioisotope is used as a drug (usually a liquid or pill). A review of this topic was published in 1999. Because the radioactive material becomes intimately mixed with the affected object it is often difficult to decontaminate the object or person in a case where internal exposure is occurring. While some very insoluble materials such as fission products within a uranium dioxide matrix might never be able to truly become part of an organism, it is normal to consider such particles in the lungs and digestive tract as a form of internal contamination which results in internal exposure.
   BULLET::::- A person who is treated for cancer by either teletherapy or brachytherapy. While in brachytherapy the source is inside the person it is still considered external exposure because it does not result in a committed dose.
  
  BULLET::::- A nuclear worker whose hands have been dirtied with radioactive dust. Assuming that his hands are cleaned before any radioactive material can be absorbed, inhaled or ingested, skin contamination is considered external exposure.
   BULLET::::- Dosis, Dobis
  
  As a consequence of the high shielding by the nearby ISS, the biological samples were predominantly exposed to galactic cosmic heavy ions, while electrons and a significant fraction of protons of the radiation belts and solar wind did not reach the samples.
  
  BULLET::::- R3D (Radiation Risk Radiometer-Dosimeter E)
   This is due to radiation from contamination located outside the human body. The source can be in the vicinity of the body or can be on the skin surface. The level of health risk is dependent on duration and the type and strength of irradiation. Penetrating radiation such as gamma rays, X-rays, neutrons or beta particles pose the greatest risk from an external source. Low penetrating radiation such as alpha particles have a low external risk due to the shielding effect of the top layers of skin. See the article on sievert for more information on how this is calculated.
   The level over the sea and other large bodies of water tends to be about a tenth of the terrestrial background. Conversely, coastal areas (and areas by the side of fresh water) may have an additional contribution from dispersed sediment.
  
  Section::::Natural background radiation.:Airborne sources.
   Radioactive contamination may also be an inevitable result of certain processes, such as the release of radioactive xenon in nuclear fuel reprocessing. In cases that radioactive material cannot be contained, it may be diluted to safe concentrations. For a discussion of environmental contamination by alpha emitters please see actinides in the environment.
  
  Nuclear fallout is the distribution of radioactive contamination by the 520 atmospheric nuclear explosions that took place from the 1950s to the 1980s. 
   External exposure is relatively "easy" to estimate, and the irradiated organism does not become radioactive, except for a case where the radiation is an intense neutron beam which causes activation.
  
  Section::::Exposure pathways.:Internal.
  
  Internal exposure occurs when the radioactive material enters the organism, and the radioactive atoms become incorporated into the organism. This can occur through inhalation, ingestion, or injection. Below are a series of examples of internal exposure.
  
  BULLET::::- The exposure caused by potassium-40 present within a "normal" person.
  
  BULLET::::- The exposure to the ingestion of a soluble radioactive substance, such as Sr in cows' milk.
   For this reason, it is important to use personal protective equipment when working with radioactive materials. Radioactive contamination may also be ingested as the result of eating contaminated plants and animals or drinking contaminated water or milk from exposed animals. Following a major contamination incident, all potential pathways of internal exposure should be considered.
  
  Successfully used on Harold McCluskey, chelation therapy and other treatments exist for internal radionuclide contamination.
  
  Section::::Decontamination.
   Radioactive contamination
  
  Radioactive contamination, also called radiological contamination, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable (from the International Atomic Energy Agency (IAEA) definition).
   Exogenous infections can be caused by organisms that colonize the skin such as "Staphylococcus aureus" or "Streptococcus" spp. and organisms that are acquired from the environment such as "Pseudomonas" spp. 
  
  Organisms causing sepsis following exposure to ionizing radiation:
  
  Section::::Principles of treatment.
   Section::::Food contamination.
  
  Food contamination happens when food are corrupted with another substance. It can happen In the process of production, transportation, packaging, storage, sales and cooking process. The contamination can be physical, chemical and biological.
  
  Section::::Food contamination.:Physical contamination.
  
  Physical contaminants (or ‘foreign bodies’) are objects such as hair, plant stalks or pieces of plastic and metal. When the foreign object comes into the food, it is a physical contaminant. If the foreign objects are bacteria, the case will a physical and biological contamination.
  
  Common sources to create physical contaminations are: hair, glass or metal, pests, jewelry, dirt and fingernails.
   BULLET::::- chemical substances and preparations, like solvents
  
  BULLET::::- gases
  
  BULLET::::- asbestos
  
  BULLET::::- radioactive substances.
  
  Section::::United Kingdom.
  
  A requirement was placed on all local authorities in England, Wales and Scotland to investigate potentially contaminated sites and, where necessary, ensure they are remediated by Part IIA of the Environmental Protection Act 1990, which was inserted by the Environment Act 1995
  
  The regime in Part IIA did not apply to radioactive contamination, but section 78YC permitted Ministers to make regulations to apply Part IIA to such contamination. Such Regulations have been made.
   Like environmental monitoring, radiation monitoring can be employed to catch contamination activities early before they become too detrimental.
  
  Section::::Nuances of contamination.:Interplanetary contamination.
  
  Interplanetary contamination occurs when a planetary body is biologically contaminated by a space probe or spacecraft, either deliberately or unintentionally. This can work both on arrival to the foreign planetary body and upon return to Earth.
  
  Section::::Nuances of contamination.:Contaminated evidence.
   Airborne contamination is measured by specialist radiological instruments that continuously pump the sampled air through a filter. Airborne particles accumulate on the filter and can be measured in a number of ways:
  
  BULLET::::1. The filter paper is periodically manually removed to an instrument such as a "scaler" which measures any accumulated radioactivity.
  
  BULLET::::2. The filter paper is static and is measured in situ by a radiation detector.
   Section::::Cause of infection.
  
  Infections caused by ionizing radiation can be endogenous, originating from the oral and gastrointestinal bacterial flora, and exogenous, originating from breached skin following trauma. 
  
  The organisms causing endogenous infections are generally gram negative bacilli such as Enterobacteriaceae (i.e. "Escherichia coli, Klebsiella pneumoniae, Proteus" spp. ), and "Pseudomonas aeruginosa."
  
  Exposure to higher doses of radiation is associated with systemic anaerobic infections due to gram negative bacilli and gram positive cocci. Fungal infections can also emerge in those that fail antimicrobial therapy and stay febrile for over 7–10 days.
   Containment is the primary way of preventing contamination being released into the environment or coming into contact or being ingested by humans.
  
  Being within the intended Containment differentiates radioactive "material" from radioactive "contamination". When radioactive materials are concentrated to a detectable level outside a containment, the area affected is generally referred to as "contaminated".
   BULLET::::- ingested or absorbed radioactive material that contaminates a biological entity, whether unintentionally or intentionally (such as with radiopharmaceuticals
  
  Note that the term "radioactive contamination" may have a connotation that is not intended. The term refers only to the presence of radioactivity, and gives no indication itself of the magnitude of the hazard involved. However, radioactivity can be measured as a quantity in a given location or on a surface, or on a unit area of a surface, such as a square meter or centimeter.
   Radioactive contamination may exist on surfaces or in volumes of material or air, and specialist techniques are used to measure the levels of contamination by detection of the emitted radiation.
  
  Section::::Control and monitoring of contamination.:Contamination monitoring.
  
  Contamination monitoring depends entirely upon the correct and appropriate deployment and utilisation of radiation monitoring instruments.
  
  Section::::Control and monitoring of contamination.:Contamination monitoring.:Surface contamination.
  