Blood and Feces Analysis

Blood Neutron activation analysis was used to determine the level of uranium in samples of blood, urine, and hair of exposed people (woikers in uranium production facilities in Slovenia) and unexposed population (Byrne and Benedik 1991). Blood samples were collected by venipuncture from the arm. The samples were freeze-dried and powdered and well mixed before encapsulation in polythene vials that were heat-sealed. The samples were irradiated with a 4 10 n cm s neutron flux for up to 30 min and rapidly ashed with 50 mg of uranium that served as a carrier. The uranium was then extracted with TBP in toluene and after cleaning the organic phase by acid washing the samples were counted with a HPGe gamma detector for 20 min. The 74.7 keV peak formed by neutron irradiation and the 185.7 keV peak (from the 

The uranium level in blood, urine, and hair of workers in phosphate mines in Syria was determined by fluorimetry (Othman 1993). The preparation of the blood samples included addition of an anticoagulant, nitric acid, and hydrogen peroxide, followed by centrifugation. The samples were then heated on a platinum plate and the flux mixture was added. Finally, the fluorescence of the samples was recorded. A correlation was found between the level of uranium in the bioassays and the number of years of employment in the mines (Othman 1993). 

Highlights Analytical procedures for bioassays of uranium in blood and feces have been developed and used in a limited number of studies. Compared to urinalysis, the collection and handling of blood and feces are complicated and entail special procedures. The preparation of fecal samples involves dry-ashing at an elevated temperature and then acid digestion. For alpha spectrometry, separation, purification, and deposition precede counting (that could last several days per sample). Other analytical techniques described in the literature include neutron activation analysis, but ICPMS is currently more widely used. 

The two main drawbacks of hair analysis are the need to remove external contamination if the body s internal hold-up is to be assessed and the need to digest the hair samples for most analytical methods (laser ablation and neutron activation techniques, discussed later, are notable exceptions). A simplified methodology that does not require microwave digestion, used to overcome these two factors was developed and described in detail later (Gonnen et al. 2000), but this is by no means the only method used for the treatment of hair samples. 

The uranium concentration in hair samples of Brazilian residents (18 young females and 4 males) was determined by ENAA (Akamine et al. 2007). Hair samples were collected from the occipital part of the head, cut into 2 mm sections, rinsed to remove external contamination, and placed on filter paper for drying. The hair samples, and samples spiked with uranium standards, were placed in thin cadmium capsules and irradiated for 16 h. After 4 days, to allow for decay of interfering radionuclides, the gamma activity of the samples was measured for 50,000 s, and the uranium content was determined from the intensity of the 106 and 278 keV peaks of Np. Method validation was based on measur ent of CRM (NIST 1575—pine needles). The uranium concentration was 2.1-49.8 ngU g hair, with mean and median values of 15.4 and 10.7 ng g , respectively. 

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