Atmospheric contribution of nanoplastics to rural and remote surface waters

There is growing evidence for global environmental pollution caused by plastic particles <1 µm, here referred to as nanoplastics. Nanoplastic concentrations have been below the detection limits of many methods for quite some time, and thus they have passed undetected in complex environmental samples. However, recently using Thermal Desorption – Proton Transfer Reaction – Mass Spectrometry, many common nanosized polymers have been detected in seawater, ice and snow of rural and remote sites. In this work, we focused on the waterbodies of two contrasting sites: remote Siberian Arctic tundra and a forest landscape in southern Sweden. Nanoplastics of four polymer types (polyethylene, polyvinyl chloride, polypropylene, polyethylene terephthalate) were detected in all sampled Swedish lakes and streams (mean 563 µg/L, seven lakes, four streams). The amount of nanoplastic polymers showed a correlation with plastic demand in Europe (R² = 0.91). In Siberia, two nanoplastic polymers (PVC and polystyrene) were detected in lakes, ponds and surface flooding, and concentrations were lower (mean 51 µg/L, three lakes, five ponds, overland flow from thawing permafrost and flooded tundra). Based on potential source analysis and HYSPLIT modelling of air mass trajectories and particle dispersion, we infer that nanoplastics predominantly arrive at both sites by atmospheric deposition from local and regional sources.