Estimation of uranium GI absorption fractions for children and adults

Abstract

Uranium is ubiquitously found in drinking water and food. The gastrointestinal tract absorption fraction (f(1)) is an important parameter in risk assessment of uranium burdens from ingestion. Although absorption of uranium from ingestion has been studied extensively in the past, human data concerning children and adults are still limited. In a previous study based on measurements of uranium concentration in 73 bone-ash samples collected by Health Canada, the absorption fractions for uranium ingestion were determined to be 0.093 ± 0.113 for infants, and 0.050 ± 0.032 for young children ranging from 1 to 7 y of age. To extend the study, a total of 69 bone-ash samples were selected for children and adults ranging from 7 to 25 y of age and residing in the same Canadian community that is known to have an elevated level of uranium in its drinking water supply. For each bone-ash sample, the total uranium concentration was measured by inductively coupled plasma mass spectrometry. To solve uranium transfer in the biokinetic model for uranium given in International Commission of Radiological Protection (ICRP) Publication 69 with estimated daily uranium intake, the program WinSAAM v3.0.1 was used. The absorption fractions were determined to be 0.030 ± 0.022 for children (7-18 y) and 0.021 ± 0.015 for adults (18-25 y). For anyone more than 18 y of age, the estimated f(1) value for uranium agree well with the ICRP recommended value of 0.02.

Atomic spectrometry update. Clinical and biological materials, foods and beverages

“…Mass spectrometry-based metabolomic studies are currently emerging in the area of food safety but given the complexities involved in this powerful approach, Antignac et al 13 reviewed the current state of the art, listing short-comings and highlighting future challenges. Focusing on individual elements, the gastrointestinal tract absorption fraction, f(1), of U was found by Chen et al 163 to be above values agreed by the International Commission on Radiological Protection for children up to the age of 18 (f(1) < 0.02). Using ICP-MS to measure U in bone ash of children (7-18 years old) and young adults (18-25 years old) living in a Canadian district known for elevated U levels, f(1) values were reported as 0.030 AE 0.022 and 0.021 AE 0.015.…”

“…5.4.19 Uranium. Chen et al 163 measured U in 69 bone ash samples, collected in the Health Canada survey, and selected to represent infants and adults from 7 to 21 years in a region with elevated U in the drinking water supply. Total U was determined using ICP-MS. From the data, the authors estimated a GI tract absorption fraction of 0.03 for children and 0.021 for adults, which was in good agreement with the International Commission of Radiological Protection recommended value.…”

Estimating the Absorption of Soil-Derived Uranium in Humans

“…For the estimation of f A and f A sol , only adult volunteers were considered. Hence, the derived data on f A sol should not be directly applied to children, since the latter might exhibit increased absorption and net retention of uranium, especially during periods of growth. ,,,, In this regard, the derived value of f A sol is very likely to underestimate the actual bioavailability of nonadults.…”

Calculation of internal dose from ingested soil-derived uranium in humans: Application of a new method

“…As reported by ICRP (ICRP 1995a), the committed effective dose coefficients of uranium for children are 1.5 to 2.7 times greater than that of adults; this increase is based on an assumed bioavailability of uranium of 2% for adults and children. Moreover, a 2.4-fold increase of the bioavailability of uranium can be concluded from recent data for children aged between 1 and years compared to adults (Chen et al 2011). Therefore, an increased effective dose of about one to two orders of magnitude might be considered for children.…”