Analysis of Eisenia fetida earthworm responses to sub-lethal C60 nanoparticle exposure using 1H-NMR based metabolomics

•The response of Eisenia fetida earthworms to C60 nanoparticle exposure was examined.•Metabolomic responses during contact tests increased with exposure time.•Soil exposure suggested an adaptation by the earthworms with time.•Sugars and amino acids significantly decreased after C60 nanoparticle exposure.

The enhanced production and environmental release of Buckminsterfullerene (C60) nanoparticles will likely increase the exposure and risk to soil dwelling organisms. We used 1H NMR-based metabolomics to investigate the response of Eisenia fetida earthworms to sub-lethal C60 nanoparticle exposure in both contact and soil tests. Principal component analysis of 1H NMR data showed clear separation between controls and exposed earthworms after just 2 days of exposure, however as exposure time increased the separation decreased in soil but increased in contact tests suggesting potential adaptation during soil exposure. The amino acids leucine, valine, isoleucine and phenylalanine, the nucleoside inosine, and the sugars glucose and maltose emerged as potential bioindicators of exposure to C60 nanoparticles. The significant responses observed in earthworms using NMR-based metabolomics after exposure to very low concentrations of C60 nanoparticles suggests the need for further investigations to better understand and predict their sub-lethal toxicity.