Simple detection of polystyrene nanoparticles and effects in freshwater mussels: method development and in situ application to urban pollution

Abstract

The ubiquity of plastics in environments worldwide is raising concerns about their toxicity to organisms. The purpose of this study was to investigate simple means to determine the exposure and effects of nanoplastics (NPs) in the freshwater mussels Elliptio complanata (E. complanata ). NP tissue levels were determined using a plasmonic nanogold sensor probe and effects were determined using the refractive index (RI) and thiol-reaction rates (TRR) in protein-dense tissue extracts. This method was adapted to quantitatively measure the concentration of NPs in tissues using a salting-out extraction in the presence of acetonitrile (ACN). Concentrated solutions of albumin were first spiked with NPs to evaluate changes in RI and TRR to determine crowding effects. The data revealed that NPs readily decreased the RI and TRR in albumin in vitro . These three simple assays were then applied on freshwater mussels caged for 3 months at various sites in a largely populated area. Mussels downstream of the city center and found at the street runoff discharge sites were highly contaminated by NPs and the RI and TRR were also reduced. In conclusion, simple and readily accessible assays to assess the NP contamination based on a visual nanogold sensor technology, and the effects of plastics are proposed for freshwater mussels.