Toxicity assessments with medaka (Oryzias latipes) reveal elevated ecological risks of lanthanum and gadolinium in aquatic ecosystems
Journal
Environmental Pollution
Journal Volume
383
Start Page
126802
ISSN
0269-7491
Date Issued
2025-10
Author(s)
Wu, Yuan-Ru
Abstract
Rare earth elements (REEs) are critical metals essential for modern industries; however, their increasing emissions from mining, industrial activities, and waste disposal have led to accumulation in aquatic ecosystems, posing potential ecological risks. Despite growing concerns, toxicological data on REEs remain inconsistent across tested organisms and exposure conditions, leaving their environmental impact unclear. This study systematically evaluated the lethal and sublethal toxicity of REEs using medaka (Oryzias latipes) larvae under controlled exposure conditions with measured dosing concentrations. Among the 14 REEs tested, yttrium (Y, LC50 = 1.40 μM), lanthanum (La, LC50 = 1.55 μM), gadolinium (Gd, LC50 = 2.15 μM), and dysprosium (Dy, LC50 = 2.20 μM) exhibited the highest lethality and greater exposure risks. These four REEs produced distinct effects in 7-day sublethal tests on medaka larvae: La and Y impaired swimming, La and Dy stunted growth, and La exhibited the highest bioconcentration, while La, Gd, and Dy induced oxidative stress. Incorporating medaka-derived toxicity data markedly lowered predicted no-effect concentrations using the species sensitivity distributions and assessment factors. Comparison with environmental exposure levels indicates that La and Gd pose elevated ecological risks (risk quotients >1). These results highlight the need to include sensitive endpoints and diverse aquatic models in REE risk assessments, particularly given the ecological threats posed by persistent, highly toxic elements such as La, Gd, and Y.
Subjects
Bioconcentration factors
Ecological risk assessment
Emerging contaminants
Oryzias latipes
Rare earth elements
Toxicity
Publisher
Elsevier BV
Type
journal article