Distribution, elimination, and renal effects of single oral doses of europium in rats.

Single doses of europium (III) chloride hexahydrate were orally administered to several groups of rats. Cumulative urine samples were taken at 0-24 h, and blood samples were drawn after 24-h administration. The europium concentration was determined in these samples by inductively coupled plasma atomic emission spectroscopy. The volume, creatinine, ß-2-microglobulin, and N-acetyl-ß-D-glucosaminidase were measured in the urine samples to evaluate possible europium-induced renal effects. The blood samples showed low europium distribution, with an average of 77.5 μg/L for all groups. Although the urinary concentration and excretion showed dose-dependent increases, the percentage of europium excreted showed a dose-dependent decrease, with an average of 0.31% in all groups. The administration of europium resulted in a significant decrease of creatinine and a significant increase of urinary volume, N-acetyl-ß-D-glucosaminidase, and ß-2-microglobulin. Rare earth elements, including europium, are believed to form colloidal conjugates that deposit in the reticuloendothelial system and glomeruli. This specific reaction may contribute to low europium bioavailability and renal function disturbances. Despite low bioavailability, the high performance of the analytical method for determination of europium makes the blood and urine sampling suitable tools for monitoring of exposure to this element. The results presented in this study will be of great importance in future studies on the health impacts of rare earth elements.