Tissue Distribution of Radiolabeled Ag Nanoparticles in Fish: Arctic Charr ().

This study presents the first whole-body tissue distributions of dissolved (Ag) and 20 nm silver nanoparticles (AgNPs) in fish (Arctic charr, ). The distributions are provided for fish exposed to three different treatments: (i) intravenous (IV), (ii) dietary, and (iii) waterborne. Quantitative whole-body autoradiography (QWBA) analyses obtained on high-resolution images reveal distinct silver distribution patterns according to the treatments. The IV exposures showed that AgNPs were mainly located in bile and kidney after 8 d, while Ag was distributed through the whole body and reached particular tissues such as bones, eyes, skin, liver, spleen, kidney, and intestine. The AgNPs distribution with the dietary exposures suggests that some dissolution occurred within fish organs. We propose that dissolved silver could later precipitate as chloride, sulfide, or selenide and be incorporated in bones during the growth. Consequently, it is yet difficult to state if AgNPs cross biological barriers. Finally, the waterborne exposures revealed that the gills can capture AgNPs, but in small quantities. This suggests that the stability of AgNPs in water is critical for the uptake via the gills.