With the increasing use of silver nanoparticles (Ag-NPs), their entrance into aquatic ecosystems isinevitable. Thus, the present study simulated the potential fate, toxicity, and bioaccumulation of Ag-NPsreleased into aquatic systems with different salinities. The Ag-NPs were characterized using inductivelycoupled plasma-atomic emission spectroscopy (ICP-AES), dynamic light scattering (DLS), transmissionelectron microscopy (TEM), energy-dispersive X-ray analysis (EDX), and UV–vis spectroscopy. Juvenilerainbow trout were exposed to Ag-NPs in three different salinity concentrations, including low (0.4 ppt),moderate (6 ± 0.3 ppt), and high (12 ± 0.2 ppt) salinity, for 14 days in static renewal systems. The nominalAg-NP concentrations in the low salinity were 0.032, 0.1, 0.32, and 1 ppm, while the Ag-NP concentrationsin the moderate and high salinity were 3.2, 10, 32, and 100 ppm. UV–vis spectroscopy was used during48 h (re-dosing time) to evaluate the stability and possible changes in size of the Ag-NPs in the water. Theresults revealed that the maxof the Ag-NPs remained stable (415–420 nm) at all concentrations in thelow salinity with a reduction of absorbance between 380 and 550 nm. In contrast, the maxquickly shiftedto a longer wavelength and reduced absorbance in the moderate and higher salinity. The bioaccumula-tion of Ag in the studied tissues was concentration-dependent in all the salinities based on the followingorder: liver > kidneys ≈ gills > white muscles. All the tissue silver levels were significantly higher in thehigh salinity than in the moderate salinity. In addition, all the fish exposed to Ag-NPs in the low, moder-ate, and high salinity showed a concentration-dependent increase in their hepatosomatic index (HSI). Inconclusion, most Ag-NPs that enter into freshwater ecosystems (low ionic strength) remain suspended,representing a potentially negative threat to the biota in an ionic or nanoscale form. However, in a highersalinity, nanoparticles agglomerate and precipitate on the surface of the sediment.
کلید واژگان :Rainbow trout, Silver nanoparticles, Salinity, Bioaccumulation, UV–vis spectroscopy
ارزش ریالی : 600000 ریال
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