Implementation of bioassay methods to improve assessment of incorporated radionuclides

Abstract

The present work which was carried out in the framework of an EU project (IDEA: Internal Dosimetry-Enhancements in Application; Contract Number: FIKR CT2001 00164) shall provide commonly acceptable guidelines for optimum performance of ICP-MS measurements with focus on urinary measurements of uranium, thorium and actinides. From the results of this work it is recommended that, whenever feasible, 24 h urine sampling should be conducted to avoid large uncertainties in the quantitation of daily urinary excretion values. For storage, urine samples should be acidified and kept frozen before analysis. Measurement of total uranium in urine by ICP-MS at physiological levels (<10 ng.l(-1)) requires no sample preparation besides UV photolysis and/or dilution. For the measurement of thorium in urine by ICP-MS, it can be concluded, that salt removal from the urine samples is not recommended. For the measurement of actinides in urine it is shown that ICP-MS is well-suited and a good alternative to alpha-spectrometry for isotopes with T1/2>5x10(4) years. In general, ICP-MS measurements are an easy, fast and cost-saving methodology. New improved measuring techniques (HR-SF-ICP-MS) with detection limits in urine of 150 pg.l(-1) (1.9 microBq.l(-1)) for 238U, 30 pg.l(-1) (2.4 microBq.l(-1)) for 235U and 100 pg.l(-1) (0.4 microBq.l(-1)) for (232)Th, respectively, meet all necessary requirements. This method should therefore become the routine technique for incorporation monitoring of workers and of members of the general public, in particular for uranium contamination.

A survey of uranium levels in urine and hair of people living in a coal mining area in Yili, Xinjiang, China

“…The ICRP uranium model (ICRP, 1995a,b) also predicted such an increase under conditions of a continuous level of intake. In contrast, Hoellriegl et al, (2011) and Oeh et al, (2007) concluded that there was no dependency of uranium excretion with age, which is consistent with our conclusion.…”

“…Much concern has been raised about the exposure of humans to elevated levels of radionuclides from nuclear-related activities such as uranium mining and processing, nuclear fuel production, nuclear waste storage (Blanchard et al, 1982;Gallop et al, 1998), and depleted uranium (Oeh et al, 2007). However, other uranium-bearing mines, such as coal mines, may also cause pollution in nearby environments.…”

“…Uranium concentrations in water samples (groundwater, river water) and solid samples (soil, mud, coal and coal ash) were also monitored in an aid to interpret uranium exposure sources for the study subjects in the target area. Inductively coupled plasma mass spectrometry (ICP-MS) was used for the measurement of uranium due to its high sensitivity, high precision, and high sample throughput (Allain et al, 1991;Haldimann et al, 2001;Oeh et al, 2007).…”

Uranium and thorium in soils, mineral sands, water and food samples in a tin mining area in Nigeria with elevated activity

“…The instrument parameters and the method applied have been described elsewhere (Roth et al, 2005;Oeh et al, 2007b). Prior to measurement, all the solid food and cigarette samples were digested using extraction with aqua regia according to the German standard method DIN 38414-S7.…”

Observation of changes in urinary excretion of thorium in humans following ingestion of a therapeutic soil

“…Thorium standards of 1, 2, 5, 10 ng L À1 concentration range were employed to calibrate the instrument. The details regarding instrument parameters, quality control, and optimization are provided elsewhere (Oeh et al, 2007;Roth et al, 2005;Schramel et al, 1999). Using this method, it was possible to achieve a detection limit of 20 pg 232 Th per liter urine.…”