کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5751703 | 1619714 | 2017 | 9 صفحه PDF | دانلود رایگان |
- Effects of coated, uncoated Ag NPs and coating agent on microalgae were evaluated.
- Coated 5 nm Ag NPs produced aggregates of smaller size and released 10 times more Ag ions than uncoated 47 nm Ag NPs.
- Coated 5 nm Ag NPs were more toxic than uncoated 47 nm Ag NPs.
- The coating agent alone was as toxic as coated 5 nm Ag NPs.
- Tetraselmis suecica was about 10 times more sensitive than Isochrysis galbana and Phaeodactylum tricornutum.
In the last years, applications for silver nanoparticles (Ag NPs) continue to increase together with the concerns about their potential input and hazards in aquatic ecosystems, where microalgae are key organisms. The aim of the present study was to assess the relative sensitivity of three marine microalgae species with differences in cell wall composition/structure exposed to Poly N-vinyl-2-pirrolidone/Polyethyleneimine (PVP/PEI) coated 5Â nm Ag NPs and uncoated 47Â nm Ag NP. As limited attention has been paid to the role of coating agents in NP toxicity, the effect of PVP/PEI alone was also evaluated. After 72Â h in artificial seawater, 47Â nm Ag NPs formed around 1400Â nm size aggregates while PVP/PEI coated 5Â nm Ag NPs reached around 90Â nm. Ag+ release in seawater was around 3% for 47Â nm Ag NPs and 30% for PVP/PEI coated 5Â nm Ag NPs. PVP/PEI coated 5Â nm Ag NP aggregates entrapped the algal cells in a network of heteroaggregates, while uncoated 47Â nm Ag NPs interacted to a lesser extent with algae. The concentration of PVP/PEI coated 5Â nm Ag NPs that exerted the median effect (EC50) on algae growth pointed out differences in algae sensitivity: T. suecica was about 10 times more sensitive than I. galbana and P. tricornutum. Further, the coating agent alone was as toxic to algae as PVP/PEI coated 5Â nm Ag NPs, suggesting that presence of the coating agent was the main driver of toxicity of coated NPs. Uncoated 47Â nm Ag NPs instead, showed similar toxicity towards algae although P. tricornutum was slightly less sensitive than T. suecica and I. galbana, which agrees with the presence of a resistant silicified cell wall in the diatom. The present work demonstrates differences in sensitivity of three marine microalgae, possibly related to their cell surface and size characteristics.
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Journal: Science of The Total Environment - Volume 577, 15 January 2017, Pages 45-53