# 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) <a href="#table-7-1" id="table-7-1"></a>

<table><thead><tr><th>Category</th><th width="231">Radionuclide</th><th>Dose per unit intake (mSv/Bq)</th></tr></thead><tbody><tr><td><strong>Natural uranium series</strong></td><td>Uranium-238</td><td>4.5 x 10⁻⁵</td></tr><tr><td></td><td>Uranium-234</td><td>4.9 x 10⁻⁵</td></tr><tr><td></td><td>Thorium-230</td><td>2.1 x 10⁻⁴</td></tr><tr><td></td><td>Radium-226</td><td>2.8 x 10⁻⁴</td></tr><tr><td></td><td>Lead-210</td><td>6.9 x 10⁻⁴</td></tr><tr><td></td><td>Polonium-210</td><td>1.2 x 10⁻³</td></tr><tr><td><strong>Natural thorium series</strong></td><td>Thorium-232</td><td>2.3 x 10⁻⁴</td></tr><tr><td></td><td>Radium-228</td><td>6.9 x 10⁻⁴</td></tr><tr><td></td><td>Thorium-228</td><td>7.2 x 10⁻⁵</td></tr></tbody></table>

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

***

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.


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