English Abstract Radiation protection policy in the Netherlands applies
to human activities in which ionizing radiation presents a hazard not to
naturally occurring sources of radiation. The risk levels (maximum
permissible risk and negligible risk) apply to sources of radiation that
cause an additional risk. Translation of these levels into practical
environmental quality objectives therefore implies that both the extent and
the origin of the risk is determined. The distinction between the natural
and the additional radiation dose is of particular interest. In this report
various possibilities are described for measuring, explaining and predicting
the naturally occurring concentrations of the precursors of the element
radon in the two radioactive decay series starting with U-238 and Th-232.
Several methods are given that may be used to derive environmental quality
objectives for the soil with respect to these radionuclides. These
environmental quality objectives are an important basis for among others the
soil sanitation policy. The nature of the radionuclides considered may have
consequences for the choice of sanitation techniques. Because possible
sources and cases of soil pollution may have important consequences for the
Dutch policy on soil sanitation, a short overview is given of data published
on these subjects. The foundation and the control of intervention levels
requires insight in the relative importance of pollution pathways. As a
result, pathways have been given ample attention.