From High-Tech To High-Risk? Unveiling the Acute Ecotoxicological Effects of Rare Earth Elements on Daphnia magna.

Abstract

Technological advancement has brought significant environmental challenges, as its associated waste is difficult to manage and its long-term effects on ecosystems and biota remains uncertain. This study aimed to evaluate the acute toxicity of rare earth elements (REEs): lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium on the standard aquatic species Daphnia magna through a toxicity screening approach. Based on EC₅₀ values, the most toxic element was yttrium (EC₅₀ = 7.2 mg L^-1), followed by scandium, dysprosium, europium, lutetium, neodymium, holmium, gadolinium, ytterbium, thulium, terbium, samarium, cerium, and lanthanum (10 > EC₅₀ < 100) identified as harmful, and praseodymium classified as non-toxic with an EC₅₀ above 100 mg L^-1 (130.81 mg L^-1). This study demonstrates that all REEs, except praseodymium, induce acute effects in D. magna using ASTM as a culture medium. The results also highlight the need for standardized screening studies to obtain reliable data for both predictive and retrospective environmental risk features.