ABSTRACT
On the assumption that rare earth elements (REEs) are nontoxic, they are being utilized as replacements of toxic heavy metals in novel technological applications. However, REEs are not entirely innocuous, and their impact on health is still uncertain. In the past decade, our laboratory has studied the urinary excretion of REEs in male Wistar rats given chlorides of europium, scandium, and yttrium solutions by one-shot intraperitoneal injection or oral dose. The present paper describes three experiments for the suitability and appropriateness of a method to use urine for biological monitoring of exposure to these REEs. The concentrations of REEs were determined in cumulative urine samples taken at 0-24 h by inductively coupled plasma atomic emission spectroscopy, showing that the urinary excretion of REEs is <2 %. Rare earth elements form colloidal conjugates in the bloodstream, which make high REEs accumulation in the reticuloendothelial system and glomeruli and low urinary excretion. The high sensitivity of inductively coupled plasma-argon emission spectrometry analytical methods, with detection limits of <2 µg/L, makes urine a comprehensive assessment tool that reflects REE exposure. The analytical method and animal experimental model described in this study will be of great importance and encourage further discussion for future studies.
Subject(s)
Environmental Monitoring/methods , Environmental Pollutants/urine , Europium/urine , Scandium/urine , Yttrium/urine , Administration, Oral , Animals , Chlorides/administration & dosage , Dose-Response Relationship, Drug , Environmental Exposure/adverse effects , Environmental Pollutants/pharmacokinetics , Environmental Pollutants/toxicity , Europium/administration & dosage , Europium/pharmacokinetics , Europium/toxicity , Injections, Intraperitoneal , Limit of Detection , Male , Metabolic Clearance Rate , Rats , Rats, Wistar , Reproducibility of Results , Scandium/administration & dosage , Scandium/pharmacokinetics , Scandium/toxicity , Spectrophotometry, Atomic , Yttrium/administration & dosage , Yttrium/pharmacokinetics , Yttrium/toxicityABSTRACT
Some of the rare earth elements such as Sc are believed to be non-toxic and, at present, are widely utilized for the replacement of toxic heavy metals in technological applications, but they are not entirely free of toxicity, with hidden potential health risks. In this animal experiment, we report the urinary scandium (Sc) excretion rate and nephrotoxiciy in male Wistar rats. For this purpose, the rats were given a single dose of a solution of scandium chloride by intraperitoneal injection. The Sc excretion (U-Sc) was determined in 24-h urine samples by inductively coupled plasma-argon emission spectrometry along with the Sc nephrotoxicity, urine volume (UV), creatinine (Crt), beta-2-microglobulin (beta2-MG) and N-acetyl-beta-D-glucosaminidase (NAG). A dose-dependent Sc excretion of 0.0063% (r = 0.97) via 24-h urine was confirmed. The administration of Sc induced a significant decrease of UV and Crt and a significant increase of NAG and beta2-MG. These results suggest that U-Sc can be a useful tool for monitoring Sc exposure. The formation of Sc colloidal conjugates that deposit in glomeruli may be the cause of a reduction of the glomerular filtration rate. We propose that the analytical method and results described in this study will be of great importance for future toxicological studies on Sc exposure.