Estimation of cumulative aquatic exposure and risk due to silver: Contribution of nano-functionalized plastics and textiles Sabine A. Blaser, Martin Scheringer ⁎ , Matthew MacLeod, Konrad Hungerbühler Institute for Chemical and Bioengineering, ETH Zürich, CH-8093 Zürich, Switzerland ARTICLE INFO ABSTRACT Article history: Received 13 July 2007 Received in revised form 19 September 2007 Accepted 5 October 2007 Available online 26 November 2007 Products with antimicrobial effect based on silver nanoparticles are increasingly used in Asia, North America and Europe. This study presents an analysis of risk to freshwater ecosystems from silver released from these nanoparticles incorporated into textiles and plastics. The analysis is presented in four stages; (i) silver mass flow analysis and estimation of emissions, (ii) assessment of the fate of silver in a river system and estimation of predicted environmental concentrations (PECs), (iii) critical evaluation of available toxicity data for environmentally relevant forms of silver and estimation of predicted no-effect concentrations (PNECs), and (iv) risk characterization. Our assessment is based on estimated silver use in the year 2010, focusing on the Rhine river as a case study. In 2010, biocidal plastics and textiles are predicted to account for up to 15% of the total silver released into water in the European Union. The majority of silver released into wastewater is incorporated into sewage sludge and may be spread on agricultural fields. The amount of silver reaching natural waters depends on the fraction of wastewater that is effectively treated. Modeled PECs in the Rhine river are in satisfactory agreement with monitoring data from other river systems. Because a complete characterization of the toxicity of environmentally relevant silver species is lacking, only a limited risk assessment is possible at this time. However, our study indicates that PEC/PNEC ratios greater than 1 cannot be ruled out for freshwater ecosystems, in particular sediments. No risk is predicted for microbial communities in sewage treatment plants. © 2007 Elsevier B.V. All rights reserved. Keywords: Silver nanoparticles Environmental mass flows Freshwater risk assessment Europe Rhine model 1. Introduction The use of silver nanoparticles incorporated in consumer products has become common in the last years because of the biocidal effect of the silver ion. Industry makes use of this new technology in food contact applications, in the interior of automobiles such as steering wheels and in building materials such as sanitary tubing and coverings. Another field of application for products with antimicrobial effect based on silver ions is medical equipment such as catheters, infusion systems and medical textiles (The Silver Institute, 2001; Markarian, 2002; Simpson, 2003; Markarian, 2006.). Worldwide, markets for silver-containing nano-functionalized products have started to grow significantly (The Silver Institute, 2001; Markarian, 2006; Rundle, 2006). The increasing use of antimicrobial silver nanoparticles requires an environmental risk assessment for such products. Here we evaluate the impacts of silver released from silver- containing plastics and textiles on freshwater ecosystems. The relevance of the topic is given by the EU directive concerning the SCIENCE OF THE TOTAL ENVIRONMENT 390 (2008) 396 – 409 ⁎ Corresponding author. Safety and Environmental Technology Group, Institute for Chemical and Bioengineering, ETH Hönggerberg, HCI G 127, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland. Tel.: +41 44 632 30 62; fax: +41 44 632 11 89. E-mail address: scheringer@chem.ethz.ch (M. Scheringer). 0048-9697/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2007.10.010 available at www.sciencedirect.com www.elsevier.com/locate/scitotenv