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In this paper, we will present a first (but not complete) status description of active personal dosemeters (APDs) and their implementation in European countries. In modern radiation protection practices, APDs are becoming absolutely necessary operational tools for satisfying the ALARA principle. Despite their success, they are relatively new for individual monitoring of workers. Regulation, legal requirements and calibration procedures are different in European member states. A catalogue of commercially available and prototype devices is presented. Improvement on devices and in implementation of calibration method are expected in the forthcoming years. End-user feedback experience and requirements are reported.
To predict uranium in human hair due to chronic exposure through drinking water, a compartment representing human hair was added into the uranium biokinetic model developed by the International Commission on Radiological Protection (ICRP). The hair compartmental model was used to predict uranium excretion in human hair as a bioassay indicator due to elevated uranium intakes. Two excretion pathways, one starting from the compartment of plasma and the other from the compartment of intermediate turnover soft tissue, are assumed to transfer uranium to the compartment of hair. The transfer rate was determined from reported uranium contents in urine and in hair, taking into account the hair growth rate of 0.1 g d(-1). The fractional absorption in the gastrointestinal tract of 0.6% was found to fit best to describe the measured uranium levels among the users of drilled wells in Finland. The ingestion dose coefficient for (238)U, which includes its progeny of (234)Th, (234m)Pa, and (234)Pa, was calculated equal to 1.3 x 10(-8) Sv Bq(-1) according to the hair compartmental model. This estimate is smaller than the value of 4.5 x 10(-8) Sv Bq(-1) published by ICRP for the members of the public. In this new model, excretion of uranium through urine is better represented when excretion to the hair compartment is accounted for and hair analysis can provide a means for assessing the internal body burden of uranium. The model is applicable for chronic exposure as well as for an acute exposure incident. In the latter case, the hair sample can be collected and analyzed even several days after the incident, whereas urinalysis requires sample collection shortly after the exposure. The model developed in this study applies to ingestion intakes of uranium.
Uranium is a naturally occurring primordial radioactive element. Small amounts found in air, water, and food are regularly consumed and inhaled by humans. Even the military, medical, and industrial use of depleted uranium can affect humans. There is an appreciable retention of incorporated uranium in skeleton, kidneys, and liver, and a review of respective effective dose coefficients has been given by the International Commission on Radiological Protection (ICRP) in its "Publication 69"; however, data regarding retention in organs or tissues and rates of urinary and fecal excretion for different age groups are incomplete. Therefore, the present study provides retention data that have been calculated for uranium in all compartments and for urinary and fecal excretion, following acute and chronic injection and ingestion for six age groups. The calculations are based on the current ICRP biokinetic model for uranium, and the data can be plotted by using any mathematical software to obtain the retention data at any time after incorporation or to calculate the internal average organ dose induced by uranium provided that specific absorbed fractions are available. The dynamic relationship of the retention in plasma and blood after intravenously and orally administered uranium can easily be derived from the database for injection and ingestion. The calculated contents of uranium in organs or tissues (using the uranium concentration in foodstuffs published by UNSCEAR for Europeans) are compared with autopsy data available in the literature. According to this model, the whole body of a 75-year-old man contains 7 microg uranium, of which 76% is in the skeleton, 1% in the kidneys, and 2.1% in the liver.
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