7.5.2 Converting intake to radiation dose

The dose arising from the annual intake, in Bq, by ingestion of each radionuclide can be estimated using a dose coefficient. Dose coefficients can vary depending on the chemical form of the radionuclide and the pathway for exposure, i.e. ingestion or inhalation. Dose is used as a general term to mean effective dose (Sv). Data for age-related dose coefficients for the ingestion of radionuclides have been published by the International Commission on Radiological Protection (ICRP 2012).

Table 7.1 Dose per unit intake by ingestion for adult members of the public (ICRP 2012)

Category	Radionuclide	Dose per unit intake (mSv/Bq)
Natural uranium series	Uranium-238	4.5 x 10⁻⁵
	Uranium-234	4.9 x 10⁻⁵
	Thorium-230	2.1 x 10⁻⁴
	Radium-226	2.8 x 10⁻⁴
	Lead-210	6.9 x 10⁻⁴
	Polonium-210	1.2 x 10⁻³
Natural thorium series	Thorium-232	2.3 x 10⁻⁴
	Radium-228	6.9 x 10⁻⁴
	Thorium-228	7.2 x 10⁻⁵

Note: Values in Table 7.1 are to be used or the most recent published ICRP dose coefficients for members of the public.

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Table 7.1 shows the dose coefficients (mSv/Bq) for radionuclides for the more significant naturally occurring radionuclides that could be found in water supplies. If any anthropogenic (human-made) radionuclides are found, their dose coefficients can be found in relevant publications of the ICRP.