Effects of Differently Coated Silver Nanoparticles on the Photosynthesis of Chlamydomonas reinhardtii

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• 作者：Enrique Navarro ; Bettina Wagner ; Niksa Odzak ; Laura Sigg ; Renata Behra
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：July 7, 2015
• 年：2015
• 卷：49
• 期：13
• 页码：8041-8047
• 全文大小：277K
• ISSN：1520-5851

文摘

Various factors have been invoked to explain the toxicity of silver nanoparticles (AgNP) to microorganisms including particle size and the nature of stabilizing coatings as well as the amount of dissolved silver occurring in AgNP suspensions. In this study we have assessed the effects of nine differently coated AgNP (chitosan, lactate, polyvinylpyrrolidone, polyethelene glycol, gelatin, sodium dodecylbenzenesulfonate, citrate, dexpanthenol, and carbonate) and AgNO₃ on the photosynthesis of the freshwater algae Chlamydomonas reinhardtii. We have thus examined how AgNP effects on algae relate to particle size, measured dissolved silver (Ag_d), and bioavailable silver (Ag_bioav). Ag_bioav was indirectly estimated in toxicity experiments by cysteine鈥搒ilver complexation at the EC₅₀. The EC₅₀ calculated as a function of measured Ag_d concentrations showed for some coatings values similar to that of dissolved Ag, whereas other coated AgNP displayed lower EC₅₀ values. In all cases, excess cysteine completely prevented effects on photosynthetic yield, confirming the role of Ag_d as a cause of the observed effect on the photosynthesis. Toxicity was related neither to particle size nor to the coatings. For all differently coated AgNP suspensions, the EC₅₀ values calculated as a function of Ag_bioav were comparable to the value of AgNO₃. Depending on the coatings Ag_bioav was comparable to or higher than measured Ag_d.