Rapid and simple determination of selenium and other trace elements in very small blood samples by XRF

Final Report on the Safety Assessment of Sodium Bromate and Potassium Bromate

Sodium Bromate and Potassium Bromate are inorganic salts that act as oxidizing agents. Whereas there are currently no reported uses of Potassium Bromate, Sodium Bromate is used in permanent waves and related hair care products. No current data were available to indicate the concentrations at which this ingredient is used. Bromate was poorly absorbed, if at all, through the skin in several in vivo and in vitro studies. The oral median lethal dose of Potassium Bromate in rats was 200–400 mg/kg. A guinea pig sensitization study suggested at most a mild sensitizing potential for Sodium Bromate. Potassium Bromate was found to be mutagenic in a mammalian cell assay and in one of three bacterial strains tested. Potassium Bromate produced a dose-dependent increase in renal neoplasms in an oral feeding study in rats. A two-stage, 26-week carcinogenesis study in rats suggested that Potassium Bromate was both a tumor promoter and a tumor initiator. Renal cell tumors, of a type not seen in controls, were seen in male golden hamsters administered Potassium Bromate in drinking water. Potassium Bromate applied to the skin of mice or injected subcutaneously into newborn mice or rats, however, was noncarci-nogenic. The high reactivity/poor skin absorption of these oxidizing agents was considered a likely explanation for the difference between the results seen with different routes of exposure. Based on the test concentrations reported, it is concluded that Sodium Bromate and Potassium Bromate are safe in cosmetic permanent wave formulations at concentrations not to exceed 10.17%, measured as Sodium Bromate.

Increased hair selenium concentration in hyperlipidemic patients

Selenium is an essential trace element with potential anti-atherogenic and antioxidant effects. Experimental data suggest that selenium might be beneficial in the prevention of atherosclerosis and its complications, whereas human epidemiological studies have yielded conflicting results. Data on hair selenium status in hyperlipidemic patients are still lacking. Therefore, we analysed selenium concentrations by X-ray fluorescence in the hair of 81 statin-naïve patients with newly diagnosed Fredrickson-type IIa and IIb hyperlipoproteinemia and compared their data with 43 healthy volunteers. We also assessed the frequency of other classical risk factors of atherosclerosis. Hair selenium levels were found to be significantly higher in hyperlipidemic patients compared with volunteers with normal lipid levels. Also, a significantly increased number of traditional atherosclerosis risk factors were observed in hyperlipidemic patients with hair selenium concentrations above the median in contrast to those with below. Our results suggest that high hair selenium status might be associated with adverse blood lipid profile together with an increased number of traditional risk factors in a selenium-deplete population. These findings warrant further investigations to study the impact of selenium supplementation on the incidence of cardiovascular events.

Comparison between levels of trace elements in normal and cancer inoculated mice by XRF and PIXE

Determination of Rb, Br, Se, Zn, Cu, Fe, and Br/Rb ratio in tissues of mice inoculated with colon and melanoma cancer cells is described. A group of 19 Balb/c mice inoculated with C26 colon carcinoma, 4 C57B1/6 mice inoculated with B16 melanoma, and 13 control mice of both kinds were under investigation. The study was conducted on samples of blood, liver, kidneys, colon, and skin, and the trace element levels in normal and inoculated mice were compared. The inoculation was by subcutaneous injection either at the back or intrafootpad. The blood samples were taken 1, 2, and 3 wk after inoculation, and after 4 wk all the animals were sacrificed. Two nondestructive, complementary analytical methods were used: a modified X-ray fluorescence (XRF) for solid tissue and particle-induced X-ray emission (PIXE) for blood samples. The detection limit (DL) in the PIXE method was 0.35 microg/g dry wt in 600 s counting time and in XRF, 1 microg/g dry sample for Rb, Br, Se and Zn and 2 microg/g for Cu and Fe in 200 s counting time. In all the cases studied, cancerous tissue developed at the site of the injection, and a significant difference in the trace element levels was observed between tissue samples obtained from normal and inoculated mice. The most pronounced effect was an increase in Rb level in the tumor by a factor ranging between 4 and 10 relative to normal tissue, with a corresponding decrease in the Br/Rb ratio (p < 0.05). Smaller changes were found in the Br, Se, Zn, and K levels. The changes in trace element levels in the inner organs were much smaller and seem to be influenced by the site of injection.

Biological monitoring of workers' exposure to bromine

The use of serum bromine concentration (SeBr) as a measure of exposure was examined in an occupational cohort. Associations with work site, department type, chemical handling, and occupation, as proxy measures of exposure, were studied. SeBr was associated with all of these measures. SeBr was also associated with various demographic characteristics (age, country of origin, and education) in men. In women, there was no association between SeBr and age, country of origin, or education. The use of SeBr as a measure of exposure is discussed. The conclusion is that the exposure to bromine can be assessed by regular monitoring of SeBr.

Determination of selenium in blood components by X-ray emission spectrometry. Procedures, concentration levels, and health implications

Sampling, storing, sample pretreatment, and experimental conditions for selenium (Se) determination in human serum, plasma, and whole blood by X-ray emission spectrometric (XRS) methods are described. Concentration levels in these biological fluids, found by this technique, are discussed and compared to values found by other techniques for the same healthy population group in the same area. XRS analysis of blood from patients with various pathological conditions is reviewed, with special attention to the relation of Se with the concentration level of other essential or nonessential trace elements.