Welcome to Citizendium

From Citizendium
Revision as of 07:49, 20 January 2024 by Pat Palmer (talk | contribs)
Jump to navigation Jump to search

Help Write Articles about our World

Welcome to Citizendium, a wiki for providing free knowledge where authors use their real names. We regard information as a public good and welcome anyone who wants to share their knowledge on virtually any subject. Our online community prides itself on being congenial and supportive. Read more about who we are.


See Recent Changes—an overview of articles being worked on now.

Become a member--it's free!

Agriculture Earth Sciences Journalism Physics
Anthropology Economics Law Politics
Archaeology Education Library & Info. Sci. Psychology
Architecture Engineering Linguistics Religion
Astronomy Food Science Literature Robotics
Biology Games Mathematics Sociology
Business Geography Media Sports
Chemistry Health Sciences Military Theater
Classics History Music Topic Informant
Computers Hobbies Philosophy Visual Arts


Please help today!
Please make your donations here.
Donations go to keep our servers running. See our financial report.


New Blog Post
Why save Citizendium? My reason number 1.





















Article counts

Citable Articles (148)
Developed Articles (1,166)
Developing Articles (8,863)
Stubs (8,212)
(18,491 total articles)

Anything is a legitimate area of investigation. Truisms

       —add a quotation about knowledge or writing

Featured Article: Radiochemistry

Radiochemistry is the chemistry of radioactive materials, where radioactive isotopes of elements are used to study the properties and chemical reactions of non-radioactive isotopes (often within radiochemistry the absence of radioactivity leads to a substance being described as being inactive as the isotopes are stable). Much of radiochemistry deals with the use of radioactivity to study ordinary chemical reactions. Radiochemistry includes the study of both natural and man-made radioisotopes. Many naturally occurring substances contain radioactive elements including uranium (U), radium (Ra) and thorium (Th).

Biochemical uses

One biological application is the study of DNA using radioactive phosphorus (32P). In these experiments, stable phosphorus is replaced by the chemical identical radioactive P-32, and the resulting radioactivity is used in analysis of the molecules and their behaviour.

Another example is the work done on the methylation of elements such as sulfur, selenium, tellurium and polonium by living organisms. Bacteria can convert these elements into volatile compounds,[1] it is thought that methylcobalamin (vitamin B12 alkylates these elements to create the dimethyls. A combination of Cobaloxime and inorganic polonium in sterile water forms a volatile polonium compound, while a control experiment which did not contain the cobalt compound did not form the volatile polonium compound.[2]. For the sulfur work the isotope 35S was used, while for polonium 207Po was used. In some related work by the addition of 57Co to the bacterial culture, followed by isolation of the cobalamin from the bacteria (and the measurement of the radioactivity of the isolated cobalamin) it was shown that the bacteria convert available cobalt into methylcobalamin.

In the first picture the polonium is added to the culture of the bacteria, by the time that the second picture is shown the bacteria have taken up some of the polonium. In the third picture the bacteria have converted some of the inorganic polonium into the dimethyl form

Environmental

Radiochemistry also includes the study of the behaviour of radioisotopes in the environment; for instance, a forest or grass fire can make radioisotopes become mobile again.[3] In these experiments, fires were started in the exclusion zone around Chernobyl and the radioactivity in the air downwind was measured.

It is important to note that a vast number of processes can release radioactivity into the environment, for example the action of cosmic rays on the air is responsible for the formation of radioisotopes (such as 14C and 32P), the decay of 226Ra forms 222Rn which is a gas which can diffuse through rocks before entering buildings[4][5][6] and dissolve in water and thus enter drinking water[7] in addition human activities such as bomb tests, accidents(for example [8]) and normal releases from industry have resulted in the release of radioactivity.

Footnotes

  1. Momoshima N, Li-X. Song, Osaki S, Maeda Y (2002) Biologically induced Po emission from fresh water. J Envir Radioactivity 63:187-97.
  2. Momoshima N, Li-X. Song, Osaki S, Maeda Y (2001) Formation and emission of volatile polonium compound by microbial activity and polonium methylation with methylcobalamin. Envir Sci Technol, 35:2956-60.
  3. Yoschenko VI et al (2006) Resuspension and redistribution of radionuclides during grassland and forest fires in the Chernobyl exclusion zone: part I. Fire experiments J Envir Radioact 86:143-63 PMID 16213067
  4. Janja Vaupotič and Ivan Kobal, "Effective doses in schools based on nanosize radon progeny aerosols", Atmospheric Environment, 2006, 40, 7494-7507
  5. Michael Durand, Building and Environment, "Indoor air pollution caused by geothermal gases", 2006, 41, 1607-1610
  6. Boffetta P "Human cancer from environmental pollutants: The epidemiological evidence", Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 2006, 608, 157-162
  7. Forte M et al. The measurement of radioactivity in Italian drinking waters. Microchemical J, 2007, 85:98-102
  8. Pöllänen R et al. "Multi-technique characterization of a nuclear bomb particle from the Palomares accident", J Envir Radioactivity, 2006, 90:15-28