Aggregation and ecotoxicity of CeO₂ nanoparticles in synthetic and natural waters with variable pH, organic matter concentration and ionic strength.
The influence of pH (6.0-9.0), natural organic matter (NOM) (0-10 mg C/L) and ionic strength (IS) (1.7-40 mM) on 14 nm CeO₂ NP aggregation and ecotoxicity towards the alga Pseudokirchneriella subcapitata was assessed following a central composite design. Mean NP aggregate sizes ranged between 200 and 10000 nm. Increasing pH and IS enhanced aggregation, while increasing NOM decreased mean aggregate sizes. The 48 h-E(r)C20s ranged between 4.7 and 395.8 mg CeO₂/L. An equation for predicting the 48 h-E(r)C20 (48 h-E(r)C20 = -1626.4 × (pH) + 109.45 × (pH)² + 116.49 × ([NOM]) - 14.317 × (pH) × ([NOM]) + 6007.2) was developed. In a validation study with natural waters the predicted 48 h-E(r)C20 was a factor 1.08-2.57 lower compared to the experimental values.
Laboratory of Environmental Toxicology and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Jozef Plateaustraat 22, B-9000 Gent, Belgium. karen.vanhoecke@ugent.be
Karen
K
Van Hoecke
Karel A C
KA
De Schamphelaere
Paul
P
Van der Meeren
Guy
G
Smagghe
Colin R
CR
Janssen
D002563:Cerium / Q000633:toxicity*; D000460:Chlorophyta / Q000187:drug effects*; D005618:Fresh Water / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D053758:Nanoparticles / Q000633:toxicity*; D009930:Organic Chemicals / Q000737:chemistry; D009994:Osmolar Concentration; D018675:Toxicity Tests / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000633:toxicity
D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D002563:Cerium; C030583:ceric oxide