The ecotoxicology of manufactured nanoparticles (MNPs) in estuarine environments is not well understood. Here we explore the hypothesis that nanoTiO 2 and single walled nanotubes (SWNT) cause sublethal impacts to the infaunal species Arenicola marina (lugworm) exposed through natural sediments. Using a 10 day OECD/ASTM 1990 acute toxicity test, no significant effects were seen for SWNT up to 0.03 g/kg and no uptake of SWNTs into tissues was observed. A significant decrease in casting rate ( P = 0.018), increase in cellular damage ( P = 0.04) and DNA damage in coelomocytes ( P = 0.008) was measured for nanoTiO 2, with a preliminary LOEC of 1 g/kg. Coherent anti-stokes Raman scattering microscopy (CARS) located aggregates of TiO 2 of >200 nm within the lumen of the gut and adhered to the outer epithelium of the worms, although no visible uptake of particles into tissues was detected.
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