The presence of microplastic and carbon-based nanoparticles in the environment may have implications for the fate and effects of traditional hydrophobic chemicals. Here we present parameters for the sorption of 17 CB congeners to 10-180 µm sized polyethylene (micro-PE), 70 nm polystyrene (nano-PS), multiwalled carbon nanotubes (MWCNT), fullerene (C60) and a natural sediment, in the environmentally relevant 10-5 to 10-1 μg L-1 concentration range. Effects of salinity and sediment organic matter fouling were assessed by measuring the isotherms in fresh- and seawater, with and without sediment present. Sorption to the ‘bulk’ sorbents sediment organic matter (OM) and micro-PE occurred through linear hydrophobic partitioning with OM and micro-PE having similar sorption affinity. Sorption to MWCNT and nano-PS was non-linear. PCB sorption to MWCNT and C60 was 3 to 4 orders of magnitude stronger than to OM and micro-PE. Sorption to nano-PS was 1 to 2 orders of magnitude stronger than to micro-PE, which was attributed to the higher aromaticity and surface-volume ratio of nano-PS. Organic matter effects varied among sorbents, with the largest OM fouling effect observed for the high surface sorbents MWCNT and nano-PS. Salinity decreased sorption for sediment and MWCNT, but increased sorption for the polymers nano-PS and micro-PE. The exceptionally strong sorption of (planar) PCBs to C60, MWCNT and nano-PS may imply increased hazards upon membrane transfer of these particles.
Ilona Velzeboer, Christiaan Kwadijk, and Albert Aart Koelmans, Environ. Sci. Technol., Vol. 48 (9), p. 4869–4876, 04/2014