Assessment of the hazard of nine (doped) lanthanides-based ceramic oxides to four aquatic species Irina Blinova a, ⁎, Heiki Vija a , Aljona Lukjanova a , Marge Muna a,b , Guttorm Syvertsen-Wiig c , Anne Kahru a,d a Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia b Tallinn University of Technology, Ehitajate tee 5, Tallinn 19086, Estonia c Ceramic Powder Technology AS, Kvenildmyra 6, 7093 Tiller, Norway d Estonian Academy of Sciences, Kohtu 6, Tallinn 10130, Estonia HIGHLIGHTS • Toxicity of (doped) lanthanide-based ceramic oxides to crustaceans and duck- weeds was studied • Toxicity of (doped) lanthanide-based ceramic oxides was mostly due to bio- available fraction of Ni and Co • Ceramic oxides not containing Ni or Co had very low toxicity to crustaceans and duckweeds (EC50: 50 -> 100 mg/L) • The test design may significantly affect bioavailability of tested compound to test species. • Accumulation of metals in the duck- weed Lemna minor is a good indicator of potential hazard of poorly soluble metal oxides. GRAPHICAL ABSTRACT abstract article info Article history: Received 22 March 2017 Received in revised form 29 June 2017 Accepted 27 August 2017 Available online xxxx The risk of environmental pollution with rare earth oxides rises in line with increasing application of these com- pounds in different sectors. However, data on potential environmental hazard of lanthanides is scarce and con- cerns mostly Ce and Gd. In this work, the aquatic toxicity of eight doped lanthanide-based ceramic oxides (Ce 0.9 Gd 0.1 O 2 , LaFeO 3 , Gd 0.97 CoO 3 , LaCoO 3 , (La 0.5 Sr 0.5 ) 0.99 MnO 3 , Ce 0.8 Pr 0.2 O 2 , (La 0.6 Sr 0.4 ) 0.95 CoO 3 , LaNiO 4 ) and one non-doped oxide (CeO 2 ) with primary size from 23 to 590 nm were evaluated in four short-term laboratory assays with freshwater crustaceans and duckweeds. Results showed no acute toxicity (EC50 N 100 mg/L) or very low acute toxicity for most studied oxides. Observed toxicity was probably due to bioavailable fraction of dopant metals (Ni and Co) but in the case of aquatic plants, decrease of nutrient availability (complexing of phosphorus by lanthanides) was also presumed. Studied oxides/metals accumulated in the aquatic plant tissue and in the gut of crustaceans and thus may be further transferred via the aquatic food chain. Accumulation of metals in the duckweed Lemna minor may be recommended as a cost-effective screening bioassay for assessment of potential hazard of poorly soluble oxides to aquatic ecosystems. © 2017 Elsevier B.V. All rights reserved. Keywords: Lanthanide oxides Hazard Bioavailability Crustaceans Duckweeds Bioaccumulation Science of the Total Environment 612 (2018) 1171–1176 ⁎ Corresponding author. E-mail address: irina.blinova@kbfi.ee (I. Blinova). http://dx.doi.org/10.1016/j.scitotenv.2017.08.274 0048-9697/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv