Археолошки Музеј / Архив / Уставен Суд

Granite is a natural source of radiation, like most natural stones. However, some granites have been reported to have higher radioactivity thereby raising some concerns about their safety.

Some granites contain around 10 to 20 parts per million of uranium. By contrast, more mafic rocks such as tonalite, gabbro or diorite have 1 to 5 ppm uranium, and limestones andsedimentary rocks usually have equally low amounts. Many large granite plutons are the sources for palaeochannel-hosted or roll front uranium ore deposits, where the uranium washes into the sediments from the granite uplands and associated, often highly radioactive, pegmatites. Granite could be considered a potential natural radiological hazard as, for instance, villages located over granite may be susceptible to higher doses of radiation than other communities.^[10] Cellars and basements sunk into soils over granite can become a trap for radongas, which is formed by the decay of uranium.^[11] Radon can also be introduced into houses by wells drilled into granite.^[12] Radon gas poses significant health concerns, and is the number two cause of lung cancer in the US behind smoking.^[12]

There is some concern that materials sold as granite countertops or as building material may be hazardous to health. Dan Steck of St. Johns University, has stated^[13] that approximately 5% of all granites will be of concern, with the caveat that only a tiny percentage of the tens of thousands of granite slabs have been tested. Various resources from national geological survey organizations are accessible online to assist in assessing the risk factors in granite country and design rules relating, in particular, to preventing accumulation of radon gas in enclosed basements and dwellings.

A study of granite countertops was done (initiated and paid for by the Marble Institute of America) in November 2008 by National Health and Engineering Inc of USA, and found that all of the 39 full size granite slabs that were measured for the study showed radiation levels well below the European Union safety standards (section 4.1.1.1 of the National Health and Engineering study) and radon emission levels well below the average outdoor radon concentrations in the US.^[14]