Species sensitivity distribution of rare earth elements: A full overview

Rare earth elements (REEs) encompass 15 lanthanides and play a crucial role in modern technology. Despite their essential uses, REEs are emerging environmental contaminants due to their growing presence in industrial, agricultural, and medical applications. For the first time, the species sensitivity distribution (SSD) approach was applied to REEs considering 58 papers including toxicity about Ce, Dy, Er, Gd, La, Lu, Nd, Pr, Sm, and Y. SSD curves were constructed by log-logistic model providing comprehensive comparisons of the sensitivities of different species to the relative REEs deriving the hazardous concentrations (HC) at 5 % and 50 %. The review reveals that arthropods, especially Daphnia magna, and echinoderms such as Sphaerechinus granularis exhibit high sensitivity especially to Ce, Er, and Lu. Conversely, vertebrates, particularly Oncorhynchus mykiss, showed greater tolerance to REEs exposure. The general hazard perception evidenced the following prioritization list according to HC₅ values in increasing order: Dy (0.03 μg/l) > Ce (0.15 μg/l) > Sm (0.29 μg/l) > La (0.64 μg/l) > Y (0.81 μg/l) > Gd (0.95 μg/l) > Pr (1.44 μg/l) > Er (1.45 μg/l) > Nd (1.67 μg/l) > Lu (2.19 μg/l). This review highlighted gaps in REEs ecotoxicity, particularly regarding heavy REEs (HREEs), and stressed the need for more data on their long-term one-health impacts. Such knowledge is vital for developing strategies to mitigate REEs contamination, emphasizing the importance of establishing safe exposure thresholds to protect both ecosystems and human health.