Cosmogenic nuclide dating kirsten storms jason cook dating 2016
It beta decays, mostly to calcium-40, and forms 0.012% of natural potassium which is otherwise made up of stable K-39 and K-41.Potassium is the seventh most abundant element in the Earth’s crust, and K-40 averages 850 Bq/kg there.The term NORM exists also to distinguish ‘natural radioactive material’ from anthropogenic sources of radioactive material, such as those produced by nuclear power and used in nuclear medicine, where incidentally the radioactive properties of a material maybe what make it useful.However from the perspective of radiation doses to people, such a distinction is completely arbitrary.It is found in many foodstuffs (bananas for example), and indeed fills an important dietary requirement, ending up in our bones.(Humans have about 65 Bq/kg of K-40 and along with those foods are therefore correspondingly radioactive to a small degree.Excluding uranium mining and all associated fuel cycle activities, industries known to have NORM issues include: Another NORM issue relates to radon exposure in homes, particularly those built on granitic ground.
These elements have always been present in the Earth's crust and atmosphere, and are concentrated in some places, such as uranium orebodies which may be mined.
However, the term is used more specifically for all naturally occurring radioactive materials where human activities have increased the potential for exposure compared with the unaltered situation.
Concentrations of actual radionuclides may or may not have been increased; if they have, the term Technologically-Enhanced (TENORM) may be used.
For most human activities involving minerals and raw materials, the levels of exposure to these radionuclides are not significantly greater than normal background levels and are not of concern for radiation protection.
However, certain work activities can give rise to significantly enhanced exposures that may need to be controlled by regulation.