Toxicity of an engineered nanoparticle (fullerene, C-60) in two aquatic species, Daphnia and fathead minnow

Water-soluble fullerene (nC(60)) has been shown to induce lipid peroxidation (LPO) in brain of juvenile largemouth bass (LMB, Micropterus salmoides) [Oberdorster, E., 2004. Manufactured nanomaterials (fullerenes, C-60) induce oxidative stress in brain of juvenile largemouth bass. Environ. Health Persp. 112, 1058-1062]; and upregulate genes related to the inflammatory response and metabolism, most notably CYP2K4 [Oberdorster, G., Oberdorster, E., Oberdorster, J., 2005. Nano-toxicology: an emerging discipline evolving from 116 studies of ultrafine particles. Environ. Health Persp. 113, 823-839]. The initial study in LMB was performed using tetrahydrofuran (THF)-solubilized nC60, although C60 can also be solubilized by stirring in water. The current study investigates differences in acute toxicity to Daphnia magna between THF-solubilized and water-stirred-nC(60) as a range-find for further assays in adult male fathead minnow (FHM, Pimephales promelas). The daphnia 48-h LC50 for THF-nC(60) was at least one order of magnitude less (0.8 ppm) than that for water-stirred-nC(60) (> 35 ppm). FHM were dosed with either 0.5 ppm of THF- or water-stirred-nC60 for 48 h. There was 100% mortality in the THF-nC(60)-exposed fish between 6 and 18 h, while the water-stirred-nC(60)-exposed fish showed no obvious physical effects after 48 h. Water-stirred-nC(60) elevated LPO in brain, significantly increased LPO in gill, and significantly increased expression of CYP2 family isozymes in liver as compared to control fish. (c) 2006 Elsevier Ltd. All rights reserved.