The threshold could for example be the same as the gamma dose present in the earth's crust, which would mean, "effectively zero" (some thresholds for natural radioactivity have been presented in a guidance developed by an expert group established under the terms of Article 31 of the Euratom Treaty). The risk for higher concentrations of radionuclides mainly exists when for example certain constituents are added to the products. The declared value will make it possible for regulators/ designers to estimate the annual effective dose of radiation (mSv) and thus see if the regulatory requirements on the works can be met.
