Rare Earth Elements in Human Blood: Baseline Concentrations and Their Potential Sources.

Rare earth elements (REEs) are increasingly used in modern technologies, raising concerns about their potential release into the environment and the resulting exposure of humans. Despite their widespread use, little is known about baseline REEs levels in the general population. In this study, we measured the concentrations of nine REEs in blood samples collected from healthy volunteers in southern Poland. The samples were analysed using mass spectrometry method. The median observed concentrations were 52.49 ngL− 1, 96.95 ngL− 1, 35.19 ngL− 1, 6.79 ngL− 1, 7.59 ngL− 1, 6.14 ngL− 1, 1.18 ngL− 1, 3.39 ngL− 1, and 0.42 ngL− 1 for La, Ce, Nd, Sm, Gd, Dy, Ho, Er, and Tm, respectively. Obtained results indicate that internal exposure to REEs in the general population of southern Poland comes mainly from a single, natural source. Additional sources of REEs contamination were rare and had only a minor impact on overall blood concentrations.