Aquatic Solutions International, Long Reef, NSW, 2097, Australia; School of Natural Sciences, Macquarie University, Macquarie Park, NSW, 2109, Australia.
Aquatic Solutions International, Airlie Beach, QLD, 4802, Australia.
Environ Res. 2024 Nov 15;261:119708. doi: 10.1016/j.envres.2024.119708. Epub 2024 Jul 30.
A lack of chronic rare earth element (REE) toxicity data for marine organisms has impeded the establishment of numerical REE water quality benchmarks (e.g., guidelines) to protect marine life and assess ecological risk. This study determined the chronic no (significant) effect concentrations (N(S)ECs) and median-effect concentrations (EC50s) of eight key REEs (yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), gadolinium (Gd), dysprosium (Dy) and lutetium (Lu)) for 30 coastal marine organisms (encompassing 22 phyla and five trophic levels from temperate and tropical habitats). Organisms with calcifying life stages were most vulnerable to REEs, which competitively inhibit calcium uptake. The most sensitive organism was a sea urchin, with N(S)ECs ranging from 0.64 μg/L for Y to 1.9 μg/L for La and Pr, and EC50s ranging from 4.3 μg/L for Y to 14.4 μg/L for Pr. Conversely, the least sensitive organism was a cyanobacterium, with N(S)ECs ranging from 121 μg/L for Y to 469 μg/L for Pr, and EC50s ranging from 889 μg/L for Y to 3000 μg/L for Pr. Median sensitivity varied 215-fold across all organisms. The two-fold difference in median toxicity (μmol/L EC50) among REEs (Y ∼ Gd > Lu ∼ Nd ∼ Dy ∼ Ce > La ∼ Pr) was attributed to offset differences in binding affinity (log K) to cell surface receptors and the percentage of free metal ion (REE) in the test waters. The toxicity (EC50) of the remaining REEs (samarium, europium, terbium, holmium, thulium and ytterbium) was predicted using a combination of physicochemical data and measured EC50s for the eight tested REEs, with good agreement between predicted and measured EC50s for selected organisms. Numerical REE water quality guidelines to protect marine life were established using species sensitivity distributions (e.g., for 95 % species protection, values ranged from 1.1 μg/L for Y to 3.0 μg/L for La, Pr or Lu).
缺乏海洋生物慢性稀土元素 (REE) 毒性数据，阻碍了建立数值 REE 水质基准（例如指南）以保护海洋生物和评估生态风险。本研究确定了八种关键 REE（钇 (Y)、镧 (La)、铈 (Ce)、镨 (Pr)、钕 (Nd)、钆 (Gd)、镝 (Dy) 和镥 (Lu)) 对 30 种沿海海洋生物（包括来自温带和热带生境的 22 个门和五个营养级）的慢性无（显著）效应浓度 (N(S)EC) 和中效浓度 (EC50)。具有钙化生命阶段的生物对 REE 最敏感，REE 竞争性抑制钙吸收。最敏感的生物是海胆，其 N(S)EC 范围为 0.64μg/L 至 1.9μg/L（Y 至 La 和 Pr），EC50 范围为 4.3μg/L 至 14.4μg/L（Y 至 Pr）。相反，最不敏感的生物是一种蓝藻，其 N(S)EC 范围为 121μg/L 至 469μg/L（Y 至 Pr），EC50 范围为 889μg/L 至 3000μg/L（Y 至 Pr）。所有生物的平均敏感性差异为 215 倍。REE 之间（Y∼Gd>Lu∼Nd∼Dy∼Ce>La ∼Pr）的中值毒性（μmol/L EC50）差异两倍归因于细胞表面受体结合亲和力（log K）和测试水中游离金属离子（REE）百分比的抵消差异。其余 REE（钐、铕、铽、钬、铥和镱）的毒性（EC50）使用物理化学数据和对测试的八种 REE 的测量 EC50 进行预测，对选定生物的预测 EC50 与测量 EC50 吻合良好。使用物种敏感性分布（例如，95%的物种保护值范围为 1.1μg/L 至 3.0μg/L（Y 至 La、Pr 或 Lu））建立了保护海洋生物的 REE 水质数值指南。
