Samarium (Sm) and yttrium (Y) are commonly used rare earth elements (REEs) but there is a scarcity of information concerning their biological effects in non-target aquatic organisms. The purpose of this study was to determine the bioavailability of those REEs and their toxicity on Dreissena polymorpha after exposure to increasing concentration of Sm and Y for 28 days at 15 °C. At the end of the exposure period, the gene expression of superoxide dismutase (SOD), catalase (CAT), metallothionein (MT), glutathione-S-transferase (GST), cytochrome c oxidase 1 (CO1) and cyclin D (Cyc D) were analysed. In addition, we examined lipid peroxidation (LPO), DNA strand breaks (DSB), GST and prostaglandin cyclooxygenase (COX) activities. Results showed a concentration dependent increase in the level of the REEs accumulated in the soft tissue of mussels. Both REEs decreased CAT but did not significantly modulated SOD and MT expressions. Furthermore, Sm³⁺ up-regulated GST, CO1 and Cyc D, while Y³⁺ increased and decreased GST and CO1 transcripts levels, respectively. Biomarker activities showed no oxidative damage as evidenced by LPO, while COX activity was decreased and DNA strand breaks levels were changed suggesting that Sm and Y exhibit anti-inflammatory and genotoxic effects. Factorial analysis revealed that the major impacted biomarkers by Sm were LPO, CAT, CO1 and COX, while GST gene expression, COX, Cyc D and CAT as the major biomarkers affected by Y. We conclude that these REEs display different mode of action but further investigations are required in order to define the exact mechanism involved in their toxicity.

commonly（Sm）和钇（Y）是常用的稀土元素（REEs），但缺乏有关其在非目标水生生物中的生物学作用的信息。这项研究的目的是确定在15°C下暴露于Sm和Y浓度不断增加的28天后，这些REE的生物利用度及其对多形果蝇的毒性。在暴露期结束时，超氧化物歧化酶（SOD），过氧化氢酶（CAT），金属硫蛋白（MT），谷胱甘肽-S-转移酶（GST），细胞色素c氧化酶1（CO1）和细胞周期蛋白D（Cyc D）的基因表达。）进行了分析。此外，我们检查了脂质过氧化（LPO），DNA链断裂（DSB），GST和前列腺素环加氧酶（COX）的活性。结果表明，贻贝软组织中所积累的REEs浓度随浓度的增加而增加。两种REE均降低了CAT，但并未显着调节SOD和MT的表达。此外，Sm ³⁺上调了GST，CO1和Cyc D，而Y ^3+则上调了GST和CO1成绩单水平。LPO证明，生物标志物活性无氧化损伤，而COX活性降低且DNA链断裂水平改变，表明Sm和Y表现出抗炎和遗传毒性作用。因子分析显示，Sm影响的主要生物标志物是LPO，CAT，CO1和COX，而GST基因表达，COX，Cyc D和CAT是受Y影响的主要生物标志物。为了确定涉及其毒性的确切机理，需要进行研究。