The effects of silver nanoparticles on fathead minnow (Pimephales promelas) embryos Geoff Laban Æ Loring F. Nies Æ Ronald F. Turco Æ John W. Bickham Æ Maria S. Sepu ´ lveda Accepted: 13 August 2009 / Published online: 2 September 2009 Ó Springer Science+Business Media, LLC 2009 Abstract Nanoparticles are being used in many com- mercial applications. We describe the toxicity of two commercial silver (Ag) nanoparticle (NP) products, NanoAmor and Sigma on Pimephales promelas embryos. Embryos were exposed to varying concentrations of either sonicated or stirred NP solutions for 96 h. LC 50 values for NanoAmor and Sigma Ag NPs were 9.4 and 10.6 mg/L for stirred and 1.25 and 1.36 mg/L for sonicated NPs, respectively. Uptake of Ag NPs into the embryos was observed after 24 h using Transmission Electron Micros- copy and Ag NPs induced a concentration-dependent increase in larval abnormalities, mostly edema. Dissolved Ag released from Ag NPs was measured using Inductively Coupled-Mass Spectrometry and the effects tested were found to be three times less toxic when compared to Ag nitrate (AgNO 3 ). The percentage of dissolved Ag released was inversely proportional to the concentration of Ag NPs with the lowest (0.625 mg/L) and highest (20 mg/L) con- centrations tested releasing 3.7 and 0.45% dissolved Ag, respectively and percent release was similar regardless if concentrations were stirred or sonicated. Thus increased toxicity after sonication cannot be solely explained by dissolved Ag. We conclude that both dissolved and par- ticulate forms of Ag elicited toxicity to fish embryos. Keywords Ecotoxicology Á Fish early life stages Á Nanoparticles Á Silver Introduction Nanomaterials are part of a commercial revolution that has resulted in an explosion of hundreds of novel products due to their diverse physico-chemical properties, enabling their usage in a wide range of innovative applications (Salata 2004; Gwinn and Vallyathan 2006). Nanotechnology is generally defined as the controlled modification of particles or materials resulting in at least one dimension between 1 and 100 nm (Roco 2005). However, toxicological studies have included particles and aggregates that are as large as several hundred nanometers (Handy and Shaw 2007). Nevertheless, the driving force behind this new technology is manufacturing control that results in increased surface area, and altered conductivity or surface chemistry of the nanoparticles (NPs) that impart unique physical and chemical properties to NPs (Masciangioli and Zhang 2003; Hoet et al. 2004). Commercialization of nanotechnology is progressing at a much faster rate than the understanding of its potential environmental impact and effects (Maynard et al. 2004; Guzman et al. 2006; Nowack and Bucheli 2007). In fact, the market for products using NPs is expected to be worth US $1 trillion by 2015 (Roco 2003, 2005). Presently, there are over 600 commercialized products on the market made G. Laban Á J. W. Bickham Á M. S. Sepu ´lveda (&) Department of Forestry & Natural Resources, Purdue University, 195 Marsteller St., West Lafayette, IN 47907, USA e-mail: mssepulv@purdue.edu L. F. Nies Á M. S. Sepu ´lveda School of Civil Engineering, Purdue University, 550 Stadium Mall Dr., West Lafayette, IN 47907, USA R. F. Turco Department of Agronomy, Purdue University, 915 W. State St., West Lafayette, IN 47907, USA G. Laban Á J. W. Bickham Center for the Environment, Purdue University, 503 Northwestern Av., West Lafayette, IN 47907, USA 123 Ecotoxicology (2010) 19:185–195 DOI 10.1007/s10646-009-0404-4