| Popis: |
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated biological reference values (BAR) for selenium [7782-49-2] in plasma and in urine to characterise the internal exposure. Selenium is an essential trace element, which is incorporated in considerable amounts by nutrition. Occupational exposure can lead to an additional selenium uptake. Its metabolism and distribution behaviour are complex. In plasma most selenium is bound to proteins and demonstrates slow kinetics with elimination half-lives of 65–300 days. In contrast, selenium in urine shows faster elimination kinetics than plasma and can display the exposure of the directly preceding work shift.There are extensive data of the German environmental specimen bank about selenium in plasma of persons not occupationally exposed to selenium at four different geographic regions of Germany, which did not reveal significant differences. These results are in good accordance with those of control groups in studies on occupationally exposed workers in Germany. Therefore, a BAR of 100 µg selenium/l plasma was evaluated. No restriction was made for the sampling time.Selenium in urine of German adults was determined in several studies, each with limited numbers of participants. They show largely consistent results. Moreover, the German data are in good agreement with two studies in Belgium and the United Kingdom. Selenium excretion in urine is tightly associated with creatinine excretion. In a synopsis of the Western European studies, a BAR of 30 µg selenium/g creatinine was evaluated. As an accumulation has to be considered, the sampling time in case of long-term exposure was set at the end of the shift after several shifts. |
