Publikationsserver der RWTH Aachen University
Der Aktivitätstransport von natürlich bedingtem Thorium in der Inkorporationsüberwachung
Abstract
dc:descriptionFor incorporation monitoring, knowledge of the dose to which human beings are exposed from incorporation of naturally occurring thorium isotopes (Th-232, Th-230, Th-282) is indispensable. If the incorporation rate is known, the dose can be calculated via biokinetic models. But the result is subject to large uncertainties. A comparison of the intake with correlated excretion samples is to be preferred. The activity of the naturally occurring thorium isotopes has been determined by alpha-spectrometry in food, urine, faeces, tap water and air samples from different regions of Germany . The results for the excretion samples were related to the intake data using a newly developed procedure for solving the biokinetic models. An increase of the f1-factor, which quantifies the activity transfer into the body fluids, is proposed. But even using this increased f1-factor, it follows that the dose by the naturally occurring thorium background is only one promille of the dose limit for occupational exposure (20 mSv). For practical purposes, the retention coefficients for the single model compartments as well as the excretion functions for the chronic incorporation of Th-232, Th-230 and Th-228 are explicitly specified. Another consequence from the model calculations is that the incorporated amount of Ra-228 is to be concerned while interpreting excretion measurements of Th-228. The measured results were furthermore tested for regional, gender specific and seasonal fluctuations.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2001
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Zingler, Jutta
- Contributors dc:contributor
-
- Bonka, Hans
Subjects
dc:subject × 7Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger