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Abstract: The fate of fullerene water suspension (FWS) in an aquatic system of Ceratophyllum sp., a rootless submerged plant, under non-sterile sediment-free conditions was investigated. Fast removal of FWS from water by the plants was observed and irreversible adsorption of C60 onto plants and increasing C60 mass on the plant surface with prolonged exposure durations were confirmed. An intact plant extraction procedure was developed and the majority (>80%) of C60 removed from water was extracted from the plants. C60 remained aggregated after being associated with the plants, which was verified by 13C NMR spectroscopy. Light micrographs showed association of FWS on and in the cuticle layers. [Copyright &y& Elsevier]

Understanding sub-lethal effects of nanomaterial may be particularly important to determining ecosystem responses as current levels of nanomaterial release are low compared to levels projected for the future. In this work, the sub-lethal effects of water stable, nanocrystalline fullerenes as C 60 (termed nC 60 ) were studied on Scenedesmus obliquus , a globally distributed phytoplankton. Sub-lethal concentration for S. obliquus was firstly determined as 0.09 mg L −1 using the standard 72 h exposure tests (OECD Guideline 201). Subsequent sub-lethal experiment of nC 60 on the S. obliquus was carried out for 60 d and focused on the photosynthesis processes. The results demonstrate that upon sub-lethal exposure, the photosynthetic products of polysaccharide, soluble protein and total lipid were decreased with exposure time. The photosynthetic pigments of chlorophyll a and chlorophyll b were negatively impacted. Further investigations indicate that the decrements in photosynthetic products and pigments were mainly due to the algal Mg 2+ decrement (by 40%) at the sub-lethal concentration (0.09 mg L −1 ) of nC 60 . The decrement in Mg 2+ of S. obliquus was due to the inhibition of Mg 2+ -ATPase activity caused by nC 60 . Sum up, these results not only describe the sub-lethal effects but also provide the probably mechanism for sub-lethal effects of nC 60 on exposed S. obliquus . [ABSTRACT FROM AUTHOR]

Highlights: [•] nC60 lowered the LC50 enhanced the 48h-toxicity of copper ions on D. magna. [•] The increased Cu2+-ATPase activity indicated nC60 enhanced the Cu2+ transport. [•] nC60 acted as a Cu2+carrier to enhance the copper accumulation in D. magna. [•] The absorption and desorption may account for the interaction between nC60 and Cu2+. [Copyright &y& Elsevier]

Abstract: Concerns exist regarding the inadvertent release of engineered nanomaterials into natural systems, and the possible negative ecosystem response that may occur. Understanding sub-lethal effects may be particularly important to determining ecosystem responses as current levels of nanomaterial release are low compared to levels projected for the future. In this work, the sub-lethal effects and bioaccumulation of water stable, nanocrystalline fullerenes as C60, (termed nC60) were studied in Daphnia magna, a globally distributed, parthenogenetic zooplankton. Sub-lethal concentrations were first determined for both mature mother (LD50 =0.4mgL−1) and neonate (gestating) daphnids (0.2mgL−1) in standard 48h exposure tests. Subsequent experiments focused on the accumulation and effects (at temperatures of 18–28°C) of nC60, during the D. magna reproductive cycle. The results demonstrate that upon sub-lethal exposure, the mortality rates of gestating daphnids increased with time and developmental stage. The maturation of daughter daphnids was negatively impacted. The mother daphnids were unable to reproduce again after exposure during pregnancy, and differential bioaccumulation occurred as a function of lipid content in the daphnia with the highest accumulation level of 7000mgkg−1 wet weight. Taken together, these results not only describe the accumulation and sub-lethal effects of nC60 on exposed daphnia, but also highlight the importance of sub-lethal exposure scenarios, which are critical to fully understanding the potential impact of fullerenes and other engineered nanoscale materials on natural systems. [Copyright &y& Elsevier]