Heavy Rare Earth Elements Affect <italic>Sphaerechinus granularis</italic> Sea Urchin Early Life Stages by Multiple Toxicity Endpoints.

Heavy rare earth elements (HREEs) were tested for adverse effects to early life stages of the sea urchin <italic>Sphaerechinus granularis</italic>. Embryos were exposed to analytically measured HREE concentrations ranging from 10⁻⁷ to 10⁻⁵ M. No significant developmental defect (DD) increases were observed in embryos exposed to 10⁻⁷ M HREEs, whereas 10⁻⁵ M HREEs resulted in significant DD increase up to 96% for HoCl₃ versus 14% in controls. Embryos exposed to 10⁻⁶ M HREEs showed the highest DD frequency in embryos exposed to 10⁻⁶ M DyCl₃ and HoCl₃. Cytogenetic analysis of HREE-exposed embryos revealed a significant decrease in mitotic activity, with increased mitotic aberrations. When <italic>S. granularis</italic> sperm were exposed to HREEs, the offspring of sperm exposed to 10⁻⁵ M GdCl₃ and LuCl₃ showed significant DD increases. The results warrant investigations on HREEs in other test systems, and on REE-containing complex mixtures. [ABSTRACT FROM AUTHOR]