Exposure of few layer graphene to Limnodrilus hoffmeisteri modifies the graphene and changes its bioaccumulation by other organisms.

While graphene has substantial commercial promise, numerous aspects regarding its ecological effects such as its potential for bioaccumulation are not well known. 14C-labeled few layer graphene (FLG) was dispersed in artificial freshwater and uptake of FLG by Limnodrilus hoffmeisteri, an oligochaete, was assessed. After exposure for 36 h to a 1 mg/L FLG suspension, the FLG body burden in the organism was nearly 60 ng/mg (on a dry mass basis). Multiple characterization results confirmed that the proteins secreted by the organisms during the exposure period coated the FLG, thus increasing its stability and decreasing its size in suspension. Uptake behaviors of Eisenia foetida exposed to FLG and protein-coated FLG at concentrations of approximately 1 mg/kg or to Daphnia magna at 100 μg/L were also quantified. Protein-coated FLG demonstrated different bioaccumulation behaviors for both organisms compared to uncoated FLG, with the FLG body burden in E. foetida increased but that in D. magna reduced. The data provide the first evidence that the proteins secreted by Limnodrilus hoffmeisteri after exposure to FLG can coat FLG, thus increasing the aqueous stability of FLG, decreasing its size, and changing its bioaccumulation potential.