Cosmogenic nuclide dating
Over time, as potential NORM hazards have been identified, these industries have increasingly become subject to monitoring and regulation.
However, there is as yet little consistency in NORM regulations among industries and countries.
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.
However certain industries handle significant quantities of NORM, which usually ends up in their waste streams, or in the case of uranium mining, the tailings dam.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.A 70 kg person has 4400 Bq of K-40 – and 3000 Bq of carbon-14.) Cosmogenic NORM is formed as a result of interactions between certain gases in the Earth’s atmosphere and cosmic rays, and is only relevant to this paper due to flying being a common mode of transport.Since most cosmic radiation is deflected by the Earth’s magnetic field or absorbed by the atmosphere, very little reaches the Earth’s surface and cosmogenic radionuclides contribute more to dose at low altitudes than cosmic rays as such.
By contrast, terrestrial NORM – especially radon – contributes to the majority of natural dose, usually over 1000 microsieverts (1 m Sv) per year.