Nanosilver

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Nanosilver is a nanoparticle of silver that is used for its antimicrobial properties in hospitals and consumer products (including odor-resistant clothing, hand sanitizers, water treatment systems, and even microbe-proof teddy bears). Nanoparticles are between one and 100 nanometers, i.e. between one and 100 billionths of a meter. Around the world, nanosilver is a growing environmental and health concern. In the U.S., manufacturers do not have to disclose the use of nanoparticles on product labels. Recent findings show that silver nanoparticles may negatively impact plant growth when they enter the environment. In lab studies, silver nanoparticles are highly toxic to bacteria and fungi, both of which are critical to plant growth, particularly in organic agriculture. Nanoparticles such as nanosilver often enter the environment via wastewater and sewage sludge.

Uses

Nanosilver is used for its antimicrobial properties in hospitals and consumer products. A 2012 study found that nanosilver kills bacteria when soluble ions are activated via oxidation.

As of 2007, more than 500 consumer products contained some form of engineered nanoparticles. About 20 percent of the 500 contained nanosilver. Products containing nanosilver include socks, paints, bandages, and food containers. In clothing, nanosilver is used to restrict the growth of odor-causing bacteria. The Project on Emerging Nanotechnologies at the Woodrow Wilson International Center for Scholars maintains an inventory of consumer products containing nanotechnology.

Nanosilver Treatment of Textiles

In 2010, the company HeiQ Materials AG submitted an application to register a nanosilver treatment of fibers as a pesticide in the United States. The EPA approved a conditional registration of the nanosilver treatment, HeiQ AGS-20 in 2012.

Nanosilver in Washing Machines

Samsung markets its "SilverCare" washing machines as able to remove 99.9 percent of bacteria. The washing machines release 400 billion nano-sized silver ions in each load of laundry. However, when another company, Fisher and Paykel, looked into the usefulness of nanosilver in washing machines compared to regular washing machine technology, they found that washing clothes at 20C (68F) with detergent removed 99.79 percent of bacteria. Thus, they determined, using nanosilver was not worth the environmental cost.

Antibacterial Wound Dressing Gel

SilvrSTAT, made by ABL Medical LLC, is an antibacterial wound care gel that contains nanosilver.

Environmental Effects

Despite its widespread use, relatively little is known about the environmental effects of nanosilver. The U.S. EPA sets water quality criteria at 1.9 parts per billion of silver in salt water and 3.4 parts per billion in fresh water. However, these standards are for silver in general, not nanosilver in particular. As nanosilver is toxic to microbial life, it could have a significant impact on the environment. Some top experts do not think the EPA standards on silver are protective enough to spare the environment from harm.

Toxicity to Fish

A study at Purdue University found that nanosilver particles suspended in solution were toxic, even lethal, to fathead minnows (a species of fish). Once the nanosilver settled, it became much less toxic, but still toxic, to the minnows. Researchers tested the minnows at various life stages. They found that the nanosilver particles were so small they were able to cross the egg membranes and move into the fish embryos in less than a day.

Effect on Plants and Soil Life

Another study measured the effects of plants grown in either sludge or sludge plus nanosilver. The tub of plants with nanosilver showed less microbial activity (compared to the other tub) but also off-gased four times as much nitrous oxide, a potent greenhouse gas that is 296 times stronger than carbon dioxide.

Nanosilver in Effluent and Sewage Sludge

In one study, six types of commercially available socks contained up to a maxiumum of 1360 parts per million of nanosilver and leached as much as 650 µg of silver into 500 mL of distilled water. Both colloidal and ionic silver leached from the socks, with particles ranging from 10 to 500 nanometers in diameter. The study was designed to simulate the amount of nanosilver entering wastewater treatment plants. Wastewater treatment plants likely release nanosilver into the environment either in the form of effluent or sewage sludge.

In comments to the EPA, officials from the sewage industry expressed concern about the increased use of silver, particularly nanosilver, as a pesticide in household products. The comments note that when the wastewater treatment plant is successful at removing silver from wastewater, all that does is remove the silver from the effluent only to put it into sewage sludge. The sewage industry worries that high concentrations of silver in sewage sludge will make them unable to dispose of sludge via land application. The letter says: "Widespread use of household products that release silver ions into sanitary sewer systems could increase silver concentrations in POTW influents, effluents, and biosolids. If silver pesticide product use becomes common, wastewater silver discharges could reach levels not seen in the last two decades—and could have adverse impacts on our wastewater treatment process as well as on the quality of our effluent and biosolids." The letter goes on to note that most silver used in products will ultimately make its way to wastewater treatment facilities, as it does not biodegrade.

They add that "two related studies, Choi and Hu (2008) and Choi et al. (2008) found that silver particles less than 5 nanometers in diameter are uniquely toxic to nitrifying bacteria, which are critical to biological nutrient removal at POTWs [publicly owned wastewater treatment plants]." Furthermore, they note that particle size impacts silver's toxicity to aquatic organisms and that wastewater treatment plants may not be able to remove silver from wastewater if the particles are very small.

Human Exposure and Toxicity

One study found that fabrics containing nanosilver can release nanosilver when exposed to artificial human sweat. However, it is not known if nanosilver can be absorbed through skin. Another study published in 2010 found that nanosilver is toxic to human stem cells and toxicity increases the longer the nanoparticles are stored. A 2009 study compared silver with the known neurotoxicant pesticide chlorpyrifos, finding that silver is five times more toxic than chlorpyrifos. According to the study's findings, silver has the potential to kill developing nerve cells. While it would require a lot of silver to harm an adult, silver can pass from a mother to a developing fetus, and the fetus would require far less silver than an adult to suffer harm. Some evidence shows that nanosilver interferes with DNA replication.

Government Regulation

The nanosilver in clothing already on the market in the United States is not yet regulated. NPR reported that the EPA motioned that it would begin the process of writing rules soon, although it had not done so at that time.

In 2008, the [International Center for Technology Assessment] (ICTA) petitioned the EPA to classify nanosilver as a pesticide and regulate it as such. In August 2010, the U.S. EPA announced it was considering granting "conditional approval" to the Swiss company HeiQ Materials AG, a producer of nanoparticles, for the use of nanosilver as a pesticide in fabrics. The EPA has the authority to regulate nanomaterials under the Toxic Substances Control Act (ToSCA) and the Federal Insecticide Fungicide and Rodenticide Act (FIFRA). The EPA granted a conditional registration of HeiQ's nanosilver in 2011. In 2012, BNA.com reported that the White House was blocking EPA efforts to regulate nanosilver.

Marketing and Influence by Industry

Industry trade groups, such as the Silver Nanotechnology Working Group say that "nanosilver used as a microbicide shouldn’t be regulated more strictly than colloidal silver, particles of silver in solution a well established ingredient present in including in health supplements and other products."

Nanosilver as "Green"

In some instances, industry now markets nanosilver as a "green," ecofriendly, or even organic technology. The logic used behind such an idea implies that nanosilver is harmless both to humans and the environment, and it is used in place of chemicals like chlorine bleach, triclosan, or detergent that would be "worse" for the environment. While each of these chemicals has an environmental impact, it is important to note that nanosilver does not break down in the environment whereas other chemicals may.

Articles and resources

Related SourceWatch articles

• Nanotechnology
• HeiQ Materials AG
• HeiQ AGS-20
• Biosolids
• Sewage sludge
• Food Rights Network

External resources

• Friends of the Earth Australia
• International Center for Technology Assessment
• The Project on Emerging Nanotechnologies
• Nanotechnology Citizen Engagement Organization
• “Appendix: Nano Silver Toxicology Information and References.” National Industrial Chemicals Notification and Assessment Scheme, Department of Health, Australian Government. Accessed September 7, 2015.

External articles

2015:

• Braakhuis, Hedwig M., Flemming R. Cassee, Paul H. B. Fokkens, Liset J. J. de la Fonteyne, Agnes G. Oomen, Petra Krystek, Wim H. de Jong, Henk van Loveren, and Margriet V. D. Z. Park. “Identification of the Appropriate Dose Metric for Pulmonary Inflammation of Silver Nanoparticles in an Inhalation Toxicity Study.” Nanotoxicology (September 4, 2015): 1–11. doi:10.3109/17435390.2015.1012184.
• Chan, Christine Ying Shan, and Jill Man Ying Chiu. “Chronic Effects of Coated Silver Nanoparticles on Marine Invertebrate Larvae: A Proof of Concept Study.” PLoS ONE 10, no. 7 (July 14, 2015). doi:10.1371/journal.pone.0132457.
• Chen, Li Qiang, Li Fang, Jian Ling, Cheng Zhi Ding, Bin Kang, and Cheng Zhi Huang. “Nanotoxicity of Silver Nanoparticles to Red Blood Cells: Size Dependent Adsorption, Uptake, and Hemolytic Activity.” Chemical Research in Toxicology 28, no. 3 (March 16, 2015): 501–9. doi:10.1021/tx500479m.
• Connolly, Mona, Maria-Luisa Fernandez-Cruz, Alba Quesada-Garcia, Luis Alte, Helmut Segner, and Jose M. Navas. “Comparative Cytotoxicity Study of Silver Nanoparticles (AgNPs) in a Variety of Rainbow Trout Cell Lines (RTL-W1, RTH-149, RTG-2) and Primary Hepatocytes.” International Journal of Environmental Research and Public Health 12, no. 5 (May 20, 2015): 5386–5405. doi:10.3390/ijerph120505386.
• Dorobantu, Loredana S., Clara Fallone, Adam J. Noble, Jonathan Veinot, Guibin Ma, Greg G. Goss, and Robert E. Burrell. “Toxicity of Silver Nanoparticles against Bacteria, Yeast, and Algae.” Journal of Nanoparticle Research 17, no. 4 (April 8, 2015): 1–13. doi:10.1007/s11051-015-2984-7.
• Fujiwara, Kakeru, Georgios A. Sotiriou, and Sotiris E. Pratsinis. “Enhanced Ag+ Ion Release from Aqueous Nanosilver Suspensions by Absorption of Ambient CO2.” Langmuir 31, no. 19 (May 19, 2015): 5284–90. doi:10.1021/la504946g.
• Gajapathi, Prakash, Meyappan Vadivel, Anand Thirunavukarsou, Sudhakar Baluchamy, and Anil K. Suresh. “An Overview on Toxic Nanoparticles and Their Interactions with Microbial Cells.” In Co-Relating Metallic Nanoparticle Characteristics and Bacterial Toxicity, 1–13. SpringerBriefs in Molecular Science. Springer International Publishing, 2015.
• Gao, Jiejun, Maria S. Sepúlveda, Christopher Klinkhamer, Alexander Wei, Yu Gao, and Cecon T. Mahapatra. “Nanosilver-Coated Socks and Their Toxicity to Zebrafish (Danio Rerio) Embryos.” Chemosphere 119 (January 2015): 948–52. doi:10.1016/j.chemosphere.2014.08.031.
• Garcia-Reyero, Natàlia, Cammi Thornton, Adam D. Hawkins, Lynn Escalon, Alan J Kennedy, Jeffery A. Steevens, and Kristine L. Willett. “Assessing the Exposure to Nanosilver and Silver Nitrate on Fathead Minnow Gill Gene Expression and Mucus Production.” Environmental Nanotechnology, Monitoring & Management 4 (November 2015): 58–66. doi:10.1016/j.enmm.2015.06.001.
• Hayashi, Yuya, Teodora Miclaus, Péter Engelmann, Herman Autrup, Duncan S. Sutherland, and Janeck J. Scott-Fordsmand. “Nanosilver Pathophysiology in Earthworms: Transcriptional Profiling of Secretory Proteins and the Implication for the Protein Corona.” Nanotoxicology 0, no. 0 (June 29, 2015): 1–9. doi:10.3109/17435390.2015.1054909.
• Hicks, Andrea L., Leanne M. Gilbertson, Jamila S. Yamani, Thomas L. Theis, and Julie B. Zimmerman. “Life Cycle Payback Estimates of Nanosilver Enabled Textiles under Different Silver Loading, Release, And Laundering Scenarios Informed by Literature Review.” Environmental Science & Technology 49, no. 13 (July 7, 2015): 7529–42. doi:10.1021/acs.est.5b01176.
• Huk, Anna, Emilia Izak-Nau, Naouale el Yamani, Hilde Uggerud, Marit Vadset, Beata Zasonska, Albert Duschl, and Maria Dusinska. “Impact of Nanosilver on Various DNA Lesions and HPRT Gene Mutations – Effects of Charge and Surface Coating.” Particle and Fibre Toxicology 12, no. 1 (July 24, 2015): 25. doi:10.1186/s12989-015-0100-x.
• Huo, Lingling, Rui Chen, Lin Zhao, Xiaofei Shi, Ru Bai, Dingxin Long, Feng Chen, Yuliang Zhao, Yan-Zhong Chang, and Chunying Chen. “Silver Nanoparticles Activate Endoplasmic Reticulum Stress Signaling Pathway in Cell and Mouse Models: The Role in Toxicity Evaluation.” Biomaterials 61 (August 2015): 307–15. doi:10.1016/j.biomaterials.2015.05.029.
• Jiang, Xiumei, Teodora Miclăuş, Liming Wang, Rasmus Foldbjerg, Duncan S. Sutherland, Herman Autrup, Chunying Chen, and Christiane Beer. “Fast Intracellular Dissolution and Persistent Cellular Uptake of Silver Nanoparticles in CHO-K1 Cells: Implication for Cytotoxicity.” Nanotoxicology 9, no. 2 (February 17, 2015): 181–89. doi:10.3109/17435390.2014.907457.
• Johari, Seyed Ali, Mohammad Reza Kalbassi, Sang Bum Lee, Mi Sook Dong, and Il Je Yu. “Silver Nanoparticles Affects the Expression of Biomarker Genes mRNA in Rainbow Trout (Oncorhynchus Mykiss).” Comparative Clinical Pathology, June 25, 2015, 1–6. doi:10.1007/s00580-015-2144-6.
• Jung, Sang-Kyu, Xiaolei Qu, Boanerges Aleman-Meza, Tianxiao Wang, Celeste Riepe, Zheng Liu, Qilin Li, and Weiwei Zhong. “Multi-Endpoint, High-Throughput Study of Nanomaterial Toxicity in Caenorhabditis Elegans.” Environmental Science & Technology 49, no. 4 (February 17, 2015): 2477–85. doi:10.1021/es5056462.
• Li, LianZhen, Huifeng Wu, Chenglong Ji, Cornelis A. M. van Gestel, Herbert E. Allen, and Willie J. G. M. Peijnenburg. “A Metabolomic Study on the Responses of Daphnia Magna Exposed to Silver Nitrate and Coated Silver Nanoparticles.” Ecotoxicology and Environmental Safety 119 (September 2015): 66–73. doi:10.1016/j.ecoenv.2015.05.005.
• Mackevica, Aiga, Lars Michael Skjolding, Andre Gergs, Annemette Palmqvist, and Anders Baun. “Chronic Toxicity of Silver Nanoparticles to Daphnia Magna under Different Feeding Conditions.” Aquatic Toxicology 161 (April 2015): 10–16. doi:10.1016/j.aquatox.2015.01.023.
• Milić, Mirta, Gerd Leitinger, Ivan Pavičić, Maja Zebić Avdičević, Slaven Dobrović, Walter Goessler, and Ivana Vinković Vrček. “Cellular Uptake and Toxicity Effects of Silver Nanoparticles in Mammalian Kidney Cells.” Journal of Applied Toxicology 35, no. 6 (June 1, 2015): 581–92. doi:10.1002/jat.3081.
• Munger, Mark A., Greg Hadlock, Greg Stoddard, Matthew H. Slawson, Diana G. Wilkins, Nicholas Cox, and Doug Rollins. “Assessing Orally Bioavailable Commercial Silver Nanoparticle Product on Human Cytochrome P450 Enzyme Activity.” Nanotoxicology 9, no. 4 (May 19, 2015): 474–81. doi:10.3109/17435390.2014.948092.
• Oprsal, Jakub, Ludek Blaha, Miloslav Pouzar, Petr Knotek, Milan Vlcek, and Katerina Hrda. “Assessment of Silver Nanoparticle Toxicity for Common Carp (Cyprinus Carpio) Fish Embryos Using a Novel Method Controlling the Agglomeration in the Aquatic Media.” Environmental Science and Pollution Research, August 2, 2015, 1–9. doi:10.1007/s11356-015-5120-4.
• Pani, Jyoti Prakash, Rajniti Prasad, Deepika Joshi, and Royana Singh. “Teratogenic Effects of Silver Nanoparticles: Gross Anomalies.” Journal of Evolution of Medical and Dental Sciences 4, no. 62 (July 2015): 10778–89.
• Seiffert, Joanna, Farhana Hussain, Coen Wiegman, Feng Li, Leo Bey, Warren Baker, Alexandra Porter, et al. “Pulmonary Toxicity of Instilled Silver Nanoparticles: Influence of Size, Coating and Rat Strain.” PLoS ONE 10, no. 3 (March 6, 2015): e0119726. doi:10.1371/journal.pone.0119726.
• Sheng, Zhiya, Joy D. Van Nostrand, Jizhong Zhou, and Yang Liu. “The Effects of Silver Nanoparticles on Intact Wastewater Biofilms.” Frontiers in Microbiology 6 (July 6, 2015). doi:10.3389/fmicb.2015.00680.
• Skalska, Joanna, Małgorzata Frontczak-Baniewicz, and Lidia Strużyńska. “Synaptic Degeneration in Rat Brain after Prolonged Oral Exposure to Silver Nanoparticles.” NeuroToxicology 46 (January 2015): 145–54. doi:10.1016/j.neuro.2014.11.002.
• Starnes, Daniel L., Jason M. Unrine, Catherine P. Starnes, Blanche E. Collin, Emily K. Oostveen, Rui Ma, Gregory V. Lowry, Paul M. Bertsch, and Olga V. Tsyusko. “Impact of Sulfidation on the Bioavailability and Toxicity of Silver Nanoparticles to Caenorhabditis Elegans.” Environmental Pollution 196 (January 2015): 239–46. doi:10.1016/j.envpol.2014.10.009.
• Sussman, Eric M., Brendan J. Casey, Debargh Dutta, and Benita J. Dair. “Different Cytotoxicity Responses to Antimicrobial Nanosilver Coatings When Comparing Extract-Based and Direct-Contact Assays.” Journal of Applied Toxicology 35, no. 6 (June 1, 2015): 631–39. doi:10.1002/jat.3104.
• Yang, Yu, Yifei Wang, Kiril Hristovski, and Paul Westerhoff. “Simultaneous Removal of Nanosilver and Fullerene in Sequencing Batch Reactors for Biological Wastewater Treatment.” Chemosphere 125 (April 2015): 115–21. doi:10.1016/j.chemosphere.2014.12.003.
• Yarmohammadi-Samani, P, and M Arabi. “Nanosilver and Silver Nitrate Induced Toxicity in a Subacute Murine Dermal Model.” International Journal of Nano Dimension 6, no. 2 (Spring 2015): 183–88.
• Yin, Yongguang, Sujuan Yu, Mohai Shen, Jingfu Liu, and Guibin Jiang. “Fate and Transport of Silver Nanoparticles in the Environment.” In Silver Nanoparticles in the Environment, edited by Jingfu Liu and Guibin Jiang, 73–108. Springer Berlin Heidelberg, 2015.
• Yu, Sujuan, Lingxiangyu Li, Qunfang Zhou, Jingfu Liu, and Guibin Jiang. “Environmental Bioeffects and Safety Assessment of Silver Nanoparticles.” In Silver Nanoparticles in the Environment, edited by Jingfu Liu and Guibin Jiang, 139–52. Springer Berlin Heidelberg, 2015.
• Zhou, Qunfang, Wei Liu, Yanmin Long, Cheng Sun, and Guibin Jiang. “Toxicological Effects and Mechanisms of Silver Nanoparticles.” In Silver Nanoparticles in the Environment, edited by Jingfu Liu and Guibin Jiang, 109–38. Springer Berlin Heidelberg, 2015.

2014:

• Chorley, Brian, William Ward, Steven O. Simmons, Beena Vallanat, and Bellina Veronesi. “The Cellular and Genomic Response of Rat Dopaminergic Neurons (N27) to Coated Nanosilver.” NeuroToxicology 45 (December 2014): 12–21. doi:10.1016/j.neuro.2014.08.010.
• Croteau, Marie-Noële, Agnieszka D. Dybowska, Samuel N. Luoma, Superb K. Misra, and Eugenia Valsami-Jones. “Isotopically Modified Silver Nanoparticles to Assess Nanosilver Bioavailability and Toxicity at Environmentally Relevant Exposures.” Environmental Chemistry 11, no. 3 (2014): 247–56.
• Ge, Liangpeng, Qingtao Li, Meng Wang, Jun Ouyang, Xiaojian Li, and Malcolm MQ Xing. “Nanosilver Particles in Medical Applications: Synthesis, Performance, and Toxicity.” International Journal of Nanomedicine 9 (May 16, 2014): 2399–2407. doi:10.2147/IJN.S55015.
• McShan, Danielle, Paresh C. Ray, and Hongtao Yu. “Molecular Toxicity Mechanism of Nanosilver.” Journal of Food and Drug Analysis 22, no. 1 (March 2014): 116–27. doi:10.1016/j.jfda.2014.01.010.
• Huk, Anna, Emilia Izak-Nau, Reidy Bogumila, Matthew Boyles, Albert Duschl, Iseult Lynch, and Maria Dusinska. “Is the Toxic Potential of Nanosilver Dependent on Its Size?” Particle and Fibre Toxicology 11, no. 65 (December 3, 2014).
• Mitrano, Denise M., Elisa Rimmele, Adrian Wichser, Rolf Erni, Murray Height, and Bernd Nowack. “Presence of Nanoparticles in Wash Water from Conventional Sivler and Nano-Silver Textiles.” ACS Nano 8, no. 7 (June 18, 2014): 7208–7129.
• “Nanosilver: Safety, Health and Environmental Effects and Role in Antimicrobial Resistance.” Scientific Committee on Emerging and Newly Identified Health Risks, June 10, 2014.
• Pulit-Prociak, Jolanta, Katarzyna Stokłosa, and Marcin Banach. “Nanosilver Products and Toxicity.” Environmental Chemistry Letters 13, no. 1 (December 17, 2014): 59–68. doi:10.1007/s10311-014-0490-2.

2013:

• “Is Nanosilver Toxic?” Science News, February 28, 2013.
• Gunawan, Cindy, Wey Yang Teoh, Christopher P. Marquis, and Rose Amal. “Antimicrobial Resistance: Induced Adaptation of Bacillus Sp. to Antimicrobial Nanosilver (Small 21/2013).” Small 9, no. 21 (November 11, 2013): 3553–3553. doi:10.1002/smll.201370132.
• Hadioui, Madjid, Simon Leclerc, and Kevin J. Wilkinson. “Multimethod Quantification of Ag+ Release from Nanosilver.” Talenta 105 (2013): 15–19. doi:10.1016/j.talanta.2012.11.048.
• Massarsky, Audrey, Lisa DuPuis, Jessica Taylor, Shahram Eisa-Beygi, Laura Strek, and Vance L. Trudeau. “Assessment of Nanosilver Toxicity during Zebrafish (Dario Rerio) Development.” Chemosphere, March 2013.
• Schluesener, Jan K., and Hermann J. Schluesener. “Nanosilver: Application and Novel Aspects of Toxicology.” Archives of Toxicology 87, no. 4 (January 24, 2013): 569–76. doi:10.1007/s00204-012-1007-z.
• Völker, Carolin, Cathinka Boedicker, Jan Daubenthaler, Matthias Oetken, and Jörg Oehlmann. “Comparative Toxicity Assessment of Nanosilver on Three Daphnia Species in Acute, Chronic and Multi-Generation Experiments.” PLoS ONE 8, no. 10 (October 7, 2013): e75026. doi:10.1371/journal.pone.0075026.
• Emam, Hossam E., Avinash P. Manian, Barbora Siroka, Heinz Duelli, Bernhard Redl, Alexandra Pipal, and Thomas Bechtold. “Treatments to Impart Antimicrobial Activity to Clothing and Household Cellulosic-Textiles - Why ‘Nano’ - Silver?” Journal of Cleaner Production 39 (January 2013): 17–23.
• Dale, Amy L., Gregory V. Lowry, and Elizabeth A. Casman. “Modeling Nanosilver Transformations in Freshwater Sediments.” Environmental Science & Technology 47 (October 22, 2013): 12920–28.
• Nate Seltenrich , "Nanosilver: Weighing the Risks and Benefits," Environmental Health Perspectives, DOI:10.1289/ehp.121-a220.
• Ryan Villarreal, "Pesticides In Your Bed? The EPA Said It's OK," International Business Times, April 3, 2013.
• Andrew Behar, Danielle Fugere, and Michael Passoff," Slipping Through the Cracks: An Issue Brief on Nanomaterials in Food," As You Sow.

2012:

• Foldbjerg, Rasmus, Eveline S. Irving, Yuya Hayashi, Kasper Thorsen, Herman Autrup, and Christiane Beer. “Global Gene Expression Profiling of Human Lung Epithelial Cells after Exposure to Nanosilver.” Toxicological Sciences, June 20, 2012.
• Hoheisel, Sarah M., Steve Diamond, and David Mount. “Comparison of Nanosilver and Ionic Silver Toxicity in Daphnia Magna and Pimephales Promelas.” Environmental Toxicology and Chemistry 31, no. 11 (November 1, 2012): 2557–63. doi:10.1002/etc.1978.
• Liu, Jingyu, Zhongying Wang, Frances D. Liu, Agnes B. Kane, and Robert H. Hurt. “Chemical Transformations of Nanosilver in Biological Environments.” ACS Nano 6, no. 11 (November 27, 2012): 9887–99. doi:10.1021/nn303449n.
• McLaughlin, Julianne, and Jean-Claude J. Bonzongo. “Effects of Natural Water Chemistry on Nanosilver Behavior and Toxicity to Ceriodaphnia Dubia and Pseudokirchneriella Subcapitata.” Environmental Toxicology and Chemistry 31, no. 1 (2012): 168–75.
• Sadeghi, Babak, Farshid S. Garmaroudi, M. Hashemi, H. R. Nezhad, A. Nasrollahi, Sima Ardalan, and Sahar Ardalan. “Comparison of the Anti-Bacterial Activity on the Nanosilver Shapes: Nanoparticles, Nanorods and Nanoplates.” Advanced Powder Technology 23, no. 1 (January 2012): 22–26. doi:10.1016/j.apt.2010.11.011.
• Sotiriou, Georgios A., Andreas Meyer, Jesper T.N. Knijnenburg, Sven Panke, and Sotiris E. Pratsinis. “Quantifying the Origin of Released Ag+ Ions from Nanosilver.” Langmuir, October 16, 2012, 15929–36. doi:10.1021/la303370d.
• Sintubin, Liesje, Willy Verstraete, and Nico Boon. “Biologically Produced Nanosilver: Current State and Future Perspectives.” Biotechnology and Bioengineering 109, no. 10 (October 1, 2012): 2422–36. doi:10.1002/bit.24570.
• Wang, Zhuang, Jingwen Chen, Xuehua Li, Jianping Shao, and Willie J.G.M. Peijnenburg. “Aquatic Toxicity of Nanosilver Colloids to Different Trophic Organisms: Contributions of Particles and Free Silver Ion.” Environmental Toxicology and Chemistry 31, no. 10 (October 1, 2012): 2408–13. doi:10.1002/etc.1964.
• Song KS, Sung JH, Ji JH, Lee JH, Lee JS, Ryu HR, Lee JK, Chung YH, Park HM, Shin BS, Chang HK, Kelman B, Yu lJ [2012]. Recovery from silver-nanoparticle-exposure-induced inflammation and lung function changes in Sprague Dawley rats. Nanotoxicology DOI: 10.3109/17435390.2011.648223.
• Yang, Yu, Qian Chen, Judy D. Wall, and Zhiqiang Hu. “Potential Nanosilver Impact on Anaerobic Digestion at Moderate Silver Concentrations.” Water Research 46, no. 4 (March 15, 2012): 1176–84. doi:10.1016/j.watres.2011.12.024.
• Yang, Yu, Meng Xu, Judy D. Wall, and Zhiqiang Hu. “Nanosilver Impact on Methanogenesis and Biogas Production from Municipal Solid Waste.” Waste Management 32, no. 5 (May 2012): 816–25. doi:10.1016/j.wasman.2012.01.009.
• Ellegaard-Jensen, Lea, Keld Alstrup Jensen, and Anders Johansen. “Nano-Silver Induces Dose-Response Effects on the Nematode Caenorhabditis Elegans.” Ecotoxicology and Environmental Safety 80 (June 1, 2012): 216–23. doi:10.1016/j.ecoenv.2012.03.003.
• Matt McGrath, "Smelly socks raise silver stink ," BBC, December 7, 2012.
• Zong-ming Xiu, Qing-bo Zhang, Hema L. Puppala, Vicki L. Colvin, and Pedro J. J. Alvarez, "Negligible Particle-Specific Antibacterial Activity of Silver Nanoparticles," Nano Letters, 2012, 12 (8), pp 4271–4275, DOI: 10.1021/nl301934w, July 5, 2012
• Birgit K. Gaiser, Stephanie Hirm, Ali Kermanizadeh, et al., “Effects of Silver Nanoparticles on the Liver and Hepatocytes in Vitro,” Toxicological Sciences, July 19, 2012.
• Rickard Arvidsson, Sverker Molander & Björn A. Sandén, "Assessing the Environmental Risks of Silver from Clothes in an Urban Area," Human and Ecological Risk Assessment: An International Journal, DOI: 10.1080/10807039.2012.691412, June 6, 2012.
• Meike van der Zande, Rob J. Vandebriel, Elke Van Doren, Evelien Kramer, Zahira Herrera Rivera, Cecilia S. Serrano-Rojero, Eric R. Gremmer, Jan Mast, Ruud J. B. Peters, Peter C. H. Hollman, Peter J. M. Hendriksen, Hans J. P. Marvin, And A. C. M. Peijnenburg, and Hans Bouwmeester, "Distribution, Elimination, and Toxicity of Silver Nanoparticles and Silver Ions in Rats after 28-Day Oral Exposure," ACS Nano, 6 (8), pp 7427–7442, August 2, 2012.
• Patrick Ambrosio and Pat Rizzuto, "White House Blocking EPA Efforts to Issue Rules on Nanomaterials, Advocates Say," Bloomberg, BNA, May 24, 2012.

2011:

• Farkas, Julia, Hannes Peter, Paul Christian, Julián Alberto Gallego Urrea, Martin Hassellöv, Jani Tuoriniemi, Stefan Gustafsson, Eva Olsson, Ketil Hylland, and Kevin Victor Thomas. “Characterization of the Effluent from a Nanosilver Producing Washing Machine.” Environment International, Special Issue: Environmental Fate and Effects of Nanoparticles, 37, no. 6 (August 2011): 1057–62. doi:10.1016/j.envint.2011.03.006.
• Huang, Yanmin, Shuxiang Chen, Xin Bing, Cuiling Gao, Tian Wang, and Bo Yuan. “Nanosilver Migrated into Food-Simulating Solutions from Commercially Available Food Fresh Containers.” Packaging Technology and Science 24, no. 5 (August 1, 2011): 291–97. doi:10.1002/pts.938.
• Korani, Mitra, S Mahdi Rezayat, Sepideh Arbabi Bidgoli, and Sharareh Adeli. “Acute and Subchronic Dermal Toxicity of Nanosilver in Guinea Pig.” International Journal of Nanomedicine, April 2011.
• Kvitek, L, Ales Panacek, J Soukupova, M Vanickova, M Kolar, and R Zboril. “Antibacterial Activity and Toxicity of Silver - Nanosilver versus Ionic Silver.” Journal of Physics Conference Series, July 2011.
• Lee JH, Kwon M, Ji JH, Kang CS, Ahn KH, Han JH, Yu IJ [2011]. Exposure assessment of workplaces manufacturing nanosized TiO 2 and silver. Inhalation Toxicol 23: 226-236.
• Lee JH, Mun J, Park JD, Yu IJ [2011]. A health surveillance case study of workers who manufacture silver nanomaterials. Nanotoxicology DOI: 10.3109/17435390.2011.600840.
• Liu, Jingyu, Kelly G. Pennell, and Robert H. Hurt. “Kinetics and Mechanisms of Nanosilver Oxysulfidation.” Environmental Science & Technology 45, no. 17 (September 1, 2011): 7345–53. doi:10.1021/es201539s.
• Stebounova, Larissa V, Andrea Adamcakova-Dodd, Jong Sung Kim, Heaweon Park, Patrick T O’Shaughnessy, Vicki H Grassian, and Peter S Thorne. “Nanosilver Induces Minimal Lung Toxicity or Inflammation in a Subacute Murine Inhalation Model.” Particle and Fibre Toxicology 8, no. 5 (2011). http://www.biomedcentral.com/content/pdf/1743-8977-8-5.pdf.
• Walser, Tobias, Evangelia Demou, Daniel J. Lang, and Stefanie Hellweg. “Prospective Environmental Life Cycle Assessment of Nanosilver T-Shirts.” Environmental Science & Technology 45, no. 10 (May 15, 2011): 4570–78. doi:10.1021/es2001248.

2010:

• H.S. Sharma, S. Hussain, J. Schlager, et al., “Influence of Nanoparticles on Blood-Brain Barrier Permeability and Brain Edema Formation in Rats,” Acta Neurochir Suppl. 106 (2010): 359-364.
• Richard Denison, Sludging through the nano lifecycle: Caution ahead, Environmental Defense Fund, September 23, 2010.
• Andrew Schneider, "EPA May Give 1st Approval of Nanosilver for Fabrics", AOL News, August 18, 2010.
• "Toxicity of silver nanoparticles increases during storage", Nanowerks, August 18, 2010.
• Helen Knight, "Antibacterial socks may boost greenhouse emissions", New Scientist, August 13, 2010.
• Kim YS, Song MY, Park JD, Song KS, Ryu HR, Chung YH, Chang HK, Lee JH, Oh KH, Kelman BJ, Hwang IK, Yu IJ [2010]. Subchronic oral toxicity of silver nanoparticles. Particle Fibre Toxicol 7: 20.
• Nicholette Zeliadt, "Silver Beware: Antimicrobial Nanoparticles in Soil May Harm Plant Life", Scientific American, August 9, 2010.
• S. Kittler, C. Greulich, J. Diendorf, M. Koller, and M. Epple, "Toxicity of Silver Nanoparticles Increases during Storage Because of Slow Dissolution under Release of Silver Ions", Chemistry of Materials, July 30, 2010.
• Miller A, Drake PL, Hintz P, Habjan M [2010]. Characterizing exposures to airborne metals and nanoparticle emissions in a refinery. Ann Occup Hyg 54 (5):504-513.
• Marina E. Quadros and Linsey C. Marr, "Environmental and Human Health Risks of Aerosolized Silver Nanoparticles", Journal of the Air & Waste Management Association, July 2010.
• Isaac Davison, "Cleaner could be dirty", New Zealand Herald, June 19, 2010.
• "Treated fabrics exposed to faux sweat release silver nanoparticles", Environmental Health News, April 30, 2010.
• Alex Halperin, "Nanosilver: Do We Know The Risks?", New Haven Independent, March 17, 2010.
• Brian Wallheimer, "Popular nanoparticle causes toxicity in fish, study shows", Purdue Newsroom, March 3, 2010.
• Heather Hamlin, "Silver is a potent nerve cell toxicant", Environmental Health News, January 21, 2010.

2009:

• Sherrie Elzey and Vicki H. Grassian, "Agglomeration, isolation and dissolution of commercially manufactured silver nanoparticles in aqueous environments", October 5, 2009.
• "Nano silver: extreme germ killer presents a growing threat to public health", Friends of the Earth, Australia, June 10, 2009.
• "Review of available data and knowledge gaps in risk assessment published for Nano Silver", SafeNano, UK, June 1, 2009.
• "Nanosilver used in food storage materials found to interfere with DNA replication", NanoWerk, February 19, 2009.
• Cal Baier-Anderson, "Regulating nano-silver as a pesticide", Environmental Defense Fund, February 12, 2009.
• Park J, Kwak BK, Bae E, Lee J, Kim Y, Choi K Yi J [2009]. Characterization of exposure to silver nanoparticles in a manufacturing facility. J Nanopart Res 11: 1705-1712.
• Yun Xie, "Detecting silver nanoparticles for our safety", Ars technica, January 22, 2009.
• Sudha Nambudiri, "Nanotoxicology research gaining momentum", Expressbuzz, January 6, 2009.
• Sung JH, Ji, JH, Park JD, Yoon, JU, Kim DS, Jeon KS, Song MY, Jeong J, Han BS, Han JE, Chung YH, Chang HK, Lee JH, Cho MH, Kelman BJ, Yu IJ [2009]. Subchronic inhalation toxicity of silver nanoparticles. Toxicol Sci 108: 452-461.
• Kim W-Y, Kim J, Park JD, Ryu HY, Yu IJ [2009]. Histological study of gender differences in accumulation of silver nanoparticles in kidneys of Fischer 344 rats. J Toxicol Environ Health Part A 72: 1279-1284.

2008:

• Lubick, Naomi. “Nanosilver Toxicity: Ions, Nanoparticles—or Both?” Environmental Science & Technology 42, no. 23 (December 1, 2008): 8617–8617. doi:10.1021/es8026314.
• Samuel N. Luoma, Silver Nanotechnologies and the Environment: Old Problems or New Challenges?, Project on Emerging Nanotechnologies, September 2008.
• Troy M. Benn and Paul Westerhoff, "Nanoparticle Silver Released into Water from Commercially Available Sock Fabrics", Environmental Science & Technology, April 9, 2008.
• Kim YS, Kim JS, Cho HS, Rha DS, Park JD, Choi BS, Lim R, Chang HK, Chung YH, Kwon IH, Jeong J, Han BS, Yu IJ [2008]. Twenty-eight day oral toxicity, genotoxicity, and gender-related tissue distribution of silver nanoparticles in Sprague-Dawley rats. Inhal Toxicol 20: 575-583.
• Sung JH, Ji HJ, Yoon JU, Kim DS, Song MY, Jeong J, Han BS, Han JH, Chung YH, Kim J, Kim TS, Chang HK, Lee EJ, Lee JH, Yu IJ [2008]. Lung function changes in Sprague-Dawley rats after prolonged inhalation exposure to silver nanoparticles. Inhalation Toxicol 20: 567-574.

2006:

• John Nielsen and Michele Norris, "EPA Moves Toward Nanotechnology Regulations", NPR, All Things Considered, November 23, 2006.

Nanosilver in the U.S. Federal Register

• [1], Environmental Protection Agency, March 31, 2010.
• Antimicrobial Pesticide Products; Registration Applications, Environmental Protection Agency, June 2, 2010.
• Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray, Environmental Protection Agency, August 13, 2010.
• Public Information Exchange on EPA Nanomaterial Case Studies, Environmental Protection Agency, December 13, 2010.
• Pesticides; Policies Concerning Products Containing Nanoscale Materials; Opportunity for Public Comment, Environmental Protection Agency, June 17, 2011.
• Pesticide Product Registrations; Conditional Approval, Environmental Protection Agency, February 22, 2012.
• Silver Nanoparticles (AgNPs); Information and Comment Request, National Institute for Occupational Safety and Health (NIOSH) of the Centers for Disease Control and Prevention (CDC), December 19, 2012.
• Chemical Substances When Manufactured or Processed as Nanoscale Materials; TSCA Reporting and Recordkeeping Requirements," Proposed Rule, Environmental Protection Agency, April 6, 2015.