Structure-ecotoxicity relationships and risk assessment of 0D-3D carbon nanomaterials across aquatic trophic levels.

The rapid expansion in the production and application of carbon nanomaterials (CNMs) raises increasing concerns regarding their environmental fate and ecological safety. Herein, we present a systematic cross-trophic assessment of fourteen well-characterized 0D-3D CNMs, including fullerene soot (FS), fullerene C60, amino-acid-derived carbon quantum dots (CQDs), single- and multi-walled carbon nanotubes (SWCNTs, MWCNTs), graphene (G1 and G3) materials, graphite (GR), and nanodiamonds (ND). Acute and chronic ecotoxicity was evaluated across three aquatic trophic levels representing producers (Lemna minor), consumers (Daphnia magna), and decomposers (Aliivibrio fischeri), following OECD and ISO guidelines. Toxic responses were strongly dependent on both trophic level and physicochemical properties of CNMs. D. magna exhibited the highest sensitivity, particularly toward long, carboxylated (oxidized) MWCNTs (MWCNT-COOH) (EC50(48 h) = 5.8 mg L-1), where toxicity was associated with digestive tract accumulation and physical interference. In contrast, L. minor was most affected by leucine-derived CQDs (EC50 = 65.2 mg L-1), inducing chlorosis and growth inhibition. The bacterial model showed generally lower sensitivity, with toxicity modulated by dispersion behaviour and surface characteristics. Across CNMs, no single parameter governed hazard; rather, toxicity emerged from the interplay of dimensionality, aspect ratio, dispersibility, and surface chemistry with organism-specific exposure pathways. These findings highlight the necessity of integrated, multi-trophic ecotoxicological evaluation for carbon nanomaterials and identify high-aspect-ratio, environmentally dispersible nanotubes as priority candidates for environmental risk assessment.