Tag Archives: Center for Environmental Implications of Nanotechnology

Duke University’s (North Carolina, US) Center for Environmental Implications of NanoTechnology (CEINT) wins $15M grant

A Nov. 13, 2013 news item on Azonano announces that the Center for Environmental Implications of Nanotechnology (CEINT) at Duke University has been awarded $15M,

A pioneering, multi-institution research center headquartered at Duke’s Pratt School of Engineering has just won $15-million grant renewal from the National Science Foundation and the US Environmental Protection Agency to continue learning more about where nanoparticles accumulate, how they interact with other chemicals and how they affect the environment.

Founded in 2008, the Center for Environmental Implications of NanoTechnology (CEINT) has been evaluating the effect of long-term nanomaterial exposure on organisms and ecosystems.

“The previous focus has been on studying simple, uniform nanomaterials in simple environments,” said Mark Wiesner, James L. Meriam Professor of Civil & Environmental Engineering and director of CEINT. “As we look to the next five years, we envision a dramatically different landscape. We will be evaluating more complex nanomaterials in more realistic natural environments such as agricultural lands and water treatment systems where these materials are likely to be found.”

The Nov. 11, 2013 Duke University news release by Karyn Hede, which originated the news item, provides some history and context for CEINT (Note: Links have been removed),

When CEINT formed, little research had been done on how materials manufactured at the nanoscale—about 1/10,000th the diameter of a human hair—enter the environment and whether their size and unique properties render them a new category of environmental risk. For example, nanoparticles can be highly reactive with other chemicals in the environment and had been shown to disrupt activities in living organisms. Indeed, nanosilver is used in clothing precisely because it effectively kills odor-causing bacteria.

To tackle this expansive research agenda, CEINT leadership assembled a multi-institutional research team encompassing expertise in ecosystems biology, chemistry, geology, materials science, computational science, mathematical modeling and other specialties, to complement its engineering expertise. The Center has 29 faculty collaborators, as well as 76 graduate and undergraduate students participating in research. Over its first five years, CEINT has answered some of the most pressing questions about environmental risk and has learned where to focus future research.

The center also pioneered the use of a new test chamber, called a mesocosm, that replicates a small wetland environment. “Over the long term, we want to evaluate how nanoparticles bioaccumulate in complex food webs,” said Emily Bernhardt, an associate professor of biology at Duke and ecosystem ecologist who helped design the simulated ecosystems. “The additional funding will allow us to study the subtle effect of low-dose exposure on ecosystems over time, as well as complex interactions among nanoparticles and other environmental contaminants.”

Looking forward, the investigators at CEINT plan to expand the use of systems modeling and to create a “knowledge commons,” a place to store various kinds of data that can then be analyzed as a whole, said CEINT Executive Director Christine Hendren.

“Our investigators and collaborators are located across the globe,” Hendren added. “We are committed to disseminating information that can be translated into responsible regulatory frameworks and that will be available to compare with results of future research.”

Key findings from CEINT’s first five years include:

Naturally occurring nanomaterials far outnumber engineered particles. CEINT scientist Michael Hochella, a geoscientist at Virginia Tech, inventoried nanoparticles and concluded that natural nanoparticles are found everywhere, from dust in the atmosphere to sea spray to volcanoes. The environmental risks of these natural nanomaterials are difficult to separate from engineered nanomaterials.

Engineered nanoparticles change once they enter the environment. Gregory V. Lowry, deputy director of CEINT and professor at Carnegie Mellon University, Pittsburgh, along with colleagues from the University of Birmingham, U.K. and the University of South Carolina found that the relatively large surface area of nanoparticles makes them highly reactive once they enter the environment. These transformations will alter their movement and toxicity and must be considered when studying nanomaterials. Their review article on this topic was named the best feature article of 2012 by the journal Environmental Science and Technology.

Nanoparticles can be visualized, even in complex environmental samples. A research team led by CEINT investigators Jie Liu, associate professor of chemistry at Duke, and CEINT Director Mark Wiesner showed that more than a dozen types of engineered nanoparticles, including silver, gold, and titanium dioxide, along with carbon nanotubes, can be surveyed using a technique called hyperspectral imaging, which measures light scattering caused by different types of nanoparticles. The new technique, co-developed by postdoctoral researcher Appala Raju Badireddy, is sensitive enough to analyze nanoparticles found in water samples ranging from ultrapurified to wastewater. It will be used in future long-term studies of how nanoparticles move and accumulate in ecological systems.

It is possible to estimate current and future volume of engineered nanomaterials. Understanding the volume of nanomaterials being produced and released into the environment is a crucial factor in risk assessment. CEINT researchers led by Christine Hendren measured the upper- and lower-bound annual U.S. production of five classes of nanomaterials, totaling as much as a combined 40,000 metric tons annually as of 2011.

Silver nanoparticles caused environmental stress in a simulated wetland environment. CEINT has developed  “mesocosms,”  open-air terrarium-like structures that simulate wetland ecosystems that can be evaluated over time. Even low doses of silver nanoparticles used in many consumer products produced about a third less biomass in a mesocosm. The researchers will now  look at how nanomaterials are transferred between organisms in a mesocosm.

I have written about CEINT and its work, including the mesocosm, many times. My August 15, 2011 posting offers an introduction to the CEINT mesocosm.

Silver nanoparticles: we love you/we hate you

We seem to have a love/hate affair with silver nanoparticles. Long recognized as biocides capable of killing bacteria, silver nanoparticles are used both in hospital settings and in sports wear. As the use of silver nanoparticles increases, there are concerns about unintended consequences to the environment and to human health. An Apr. 12, 2013 news item on Nanowerk highlights some research done in Europe in 2011 (Note: Links have been removed),

As part of an EU funded project called Prosuite, Walser [Tobias Walser, researcher at the Institute for environmental engineering at the Swiss Federal Institute of Technology Zürich {ETH}] and colleagues analysed the environmental impact of nanosilver T-shirts during their entire life cycle, from raw material extraction to end-of-life disposal (“Prospective Environmental Life Cycle Assessment of Nanosilver T-Shirts”). This, according to Walser, is the first of its kind for a nanomaterial. The scientists found that the T-shirt’s environmental impact during use would be reduced if they are washed less often than conventional ones, due to their antimicrobial properties. This would even compensate for a slightly higher climate footprint during production. Walser explains: “In comparison to all toxic releases during the life cycle of a T-shirt, the toxic releases from nanosilver from washing appear to be of minor relevance.” [emphasis mine]

The Apr. 11, 2013 article by Constanze Böttcher for Youris.com, which originated the news item, expands on the theme of toxicity, nanosilver, and wastewater (Note: A link has been removed),

Previous studies looked at single impacts of antibacterial textiles. For example, scientists found that nanosilver leaches into the wastewater during washing. According to other studies, this silver may not be that harmful to the environment because it is transformed into a nearly insoluble substance called silver sulphide in wastewater treatments. A study published by the Danish Environmental Protection Agency in 2012 did not find “specific risks” to health or environmental effects of nanosilver textiles available in Denmark.

This finding contrasts with more recent research at Duke University’s CEINT (Center for Environmental Implications of Nanotechnology) mesocosm project where a study did point to adverse responses (noted in my Feb. 28, 2013 posting where I highlighted two nanosilver environmental studies, a Finnish/Estonian research project and the CEINT project),

In experiments mimicking a natural environment, Duke University researchers have demonstrated that the silver nanoparticles used in many consumer products can have an adverse effect on plants and microorganisms.

The main route by which these particles enter the environment is as a by-product of water and sewage treatment plants. [emphasis] The nanoparticles are too small to be filtered out, so they and other materials end up in the resulting “sludge,” which is then spread on the land surface as a fertilizer.

The researchers found that one of the plants studied, a common annual grass known as Microstegium vimeneum, had 32 percent less biomass in the mesocosms treated with the nanoparticles. Microbes were also affected by the nanoparticles, Colman [Benjamin Colman, a post-doctoral fellow in Duke’s biology department and a member of the Center for the Environmental Implications of Nanotechnology (CEINT)] said. One enzyme associated with helping microbes deal with external stresses was 52 percent less active, while another enzyme that helps regulate processes within the cell was 27 percent less active. The overall biomass of the microbes was also 35 percent lower, he said.

As I’ve suggested before, analysing the impact that new products and materials may have on the environment and on our health is a complex process.  From Böttcher’s 2013 article (Note: Links have been removed),

Some experts are concerned about their environmental risks, however. The study “is very relevant” because it “gives a fingerprint” about the impact of such T-shirts, Anders Baun says. But the professor in risk assessment of nanomaterials at the department of environmental engineering at the Technical University of Denmark, based in Lyngby, considers it “a bad idea to distribute silver in the environment”. He points to a study that found evidence for nanosilver accumulating in the food web based on a study of plants and animals of an experimental wetland environment. Moreover, he says, it is unknown how the coating of nanosilver influences its environmental behaviour. Baun has previously criticised the European policies regarding nanosilver and is currently enrolled in a scientific committee on the topic as invited expert. The expert group will publish its opinion later this year, he says.

There’s also the possibility that bacteria will develop resistance with increased use of silver nanoparticles in medical environments and in sportswear and in other applications.

For those who want to conduct their own investigations, here’s a link to and a citation for Walser’s 2011 paper,

Prospective Environmental Life Cycle Assessment of Nanosilver T-Shirts by Tobias Walser, Evangelia Demou, Daniel J. Lang, and Stefanie Hellweg.  Environ. Sci. Technol [Environmental Science and Technology], 2011, 45 (10), pp 4570–4578 DOI: 10.1021/es2001248 Publication Date (Web): April 20, 2011
Copyright © 2011 American Chemical Society

This paper is open access.

A description of PROSUITE (PROspective SUstaInability assessment of TEchnologies project) can be found here and the PROSUITE project website can found here.

ETA Apr. 18, 2013: An Apr. 18, 2013 news item (Barely any nanosilver from consumer products in the water) on Nanowerk provides some insight into why at least one European country views the presence of silver nanoparticles in sewage sludge without any particular alarm,

The study did not examine what happens to nanosilver in the sewage sludge thereafter. In Switzerland, it is not permissible to use sewage sludge on farmland, and most of the sludge is therefore burned. [emphasis mine] The heavy metals separated in this process should not be released into the environment in large quantities.

Here’s a link to and citation for the Swiss study,

Fate and transformation of silver nanoparticles in urban wastewater systems by Ralf Kaegia, Andreas Voegelina, Christoph Orta, Brian Sinneta, Basilius Thalmanna, Jasmin Krismerb, Harald Hagendorferc, Maline Elumelua, and Elisabeth Muellerd. Water Research, http://dx.doi.org/10.1016/j.watres.2012.11.060 Available online 26 March 2013

The article is behind a paywall.

Silver nanoparticles, water, the environment, and toxicity

I am contrasting two very different studies on silver nanoparticles in water and their effect on the environment to highlight the complex nature of determining the risks and environmental effects associated with nanoparticles in general. One piece of research suggests that silver nanoparticles are less dangerous than other commonly used forms of silver while the other piece raises some serious concerns.

A Feb. 28, 2013 news item on Nanowerk features research about the effects that silver nanoparticles have on aquatic ecosystems (Note: A link has been removed),

According to Finnish-Estonian joint research with data obtained on two crustacean species, there is apparently no reason to consider silver nanoparticles more dangerous for aquatic ecosystems than silver ions.

The results were reported in the journal Environmental Science and Pollution Research late last year (“Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus”). Jukka Niskanen has utilised the same polymerisation and coupling reactions in his doctoral dissertation studying several hybrid nanomaterials, i.e. combinations of synthetic polymers and inorganic (gold, silver and montmorillonite) nanoparticles. Niskanen will defend his doctoral thesis at the University of Helsinki in April.

The University of Helsikinki Feb. 28, 2013 press release written by Minna Merilainen and which originated the new item provides details about the research,

“Due to the fact that silver in nanoparticle form is bactericidal and also fungicidal and also prevents the reproduction of those organisms, it is now used in various consumer goods ranging from wound dressing products to sportswear,” says Jukka Niskanen from the Laboratory of Polymer Chemistry at the University of Helsinki, Finland.A joint study from the University of Helsinki and the National Institute of Chemical Physics and Biophysics (Tallinn, Estonia), Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus, shows that silver nanoparticles are apparently no more hazardous to aquatic ecosystems than a water-soluble silver salt. The study compared the ecotoxicity of silver nanoparticles and a water-soluble silver salt.

“Our conclusion was that the environmental risks caused by silver nanoparticles are seemingly not higher than those caused by a silver salt. However, more research is required to reach a clear understanding of the safety of silver-containing particles,” Niskanen says.

Indeed, silver nanoparticles were found to be ten times less toxic than the soluble silver nitrate - a soluble silver salt used for the comparison.

The bioavailability of silver varies in different test media

To explain this phenomenon, the researchers refer to the variance in the bioavailability of silver to crustaceans in different tested media.

University lecturer Olli-Pekka Penttinen from the Department of Environmental Sciences of the University of Helsinki goes on to note that the inorganic and organic compounds dissolved in natural waters (such as humus), water hardness and sulfides have a definite impact on the bioavailability of silver. Due to this, the toxicity of both types of tested nanoparticles and the silver nitrate measured in the course of the study was lower in natural water than in artificial fresh water.

The toxicity of silver nanoparticles and silver ions was studied using two aquatic crustaceans, a water flea (Daphnia magna) and a fairy shrimp ( Thamnocephalus platyurus). Commercially available protein-stabilised particles and particles coated with a water-soluble, non-toxic polymer, specifically synthesised for the purpose, were used in the study. First, the polymers were produced utilising a controlled radical polymerization method. Synthetic polymer-grafted silver particles were then produced by attaching the water-soluble polymer to the surface of the silver with a sulfur bond.

Jukka Niskanen has utilised such polymerisation and coupling reactions in his doctoral dissertation. Polymeric and hybrid materials: polymers on particle surfaces and air-water interfaces, studying several hybrid nanomaterials , i.e., combinations of synthetic polymers and inorganic (gold, silver and montmorillonite) nanoparticles....

It was previously known from other studies and research results that silver changes the functioning of proteins and enzymes. It has also been shown that silver ions can prevent the replication of DNA. Concerning silver nanoparticles, tests conducted on various species of bacteria and fungi have indicated that their toxicity varies. For example, gram-negative bacteria such as Escherichia coli are more sensitive to silver nanoparticles than gram-positive ones (such as Staphylococcus aureus). The difference in sensitivity is caused by the structural differences of the cell membranes of the bacteria. The cellular toxicity of silver nanoparticles in mammals has been studied as well. It has been suggested that silver nanoparticles enter cells via endocytosis and then function in the same manner as in bacterial cells, damaging DNA and hindering cell respiration. Electron microscope studies have shown that human skin is permeable to silver nanoparticles and that the permeability of damaged skin is up to four times higher than that of healthy skin.

While this Finnish-Estonian study suggests that silver nanoparticles do not have a negative impact on the tested crustaceans in an aquatic environment, there’s a study from Duke University suggests that silver nanoparticles in wastewater which is later put to agricultural use may cause problems. From the Feb. 27, 2013 news release on EurekAlert,

In experiments mimicking a natural environment, Duke University researchers have demonstrated that the silver nanoparticles used in many consumer products can have an adverse effect on plants and microorganisms.

The main route by which these particles enter the environment is as a by-product of water and sewage treatment plants. [emphasis] The nanoparticles are too small to be filtered out, so they and other materials end up in the resulting “sludge,” which is then spread on the land surface as a fertilizer.

The researchers found that one of the plants studied, a common annual grass known as Microstegium vimeneum, had 32 percent less biomass in the mesocosms treated with the nanoparticles. Microbes were also affected by the nanoparticles, Colman [Benjamin Colman, a post-doctoral fellow in Duke’s biology department and a member of the Center for the Environmental Implications of Nanotechnology (CEINT)] said. One enzyme associated with helping microbes deal with external stresses was 52 percent less active, while another enzyme that helps regulate processes within the cell was 27 percent less active. The overall biomass of the microbes was also 35 percent lower, he said.

“Our field studies show adverse responses of plants and microorganisms following a single low dose of silver nanoparticles applied by a sewage biosolid,” Colman said. “An estimated 60 percent of the average 5.6 million tons of biosolids produced each year is applied to the land for various reasons, and this practice represents an important and understudied route of exposure of natural ecosystems to engineered nanoparticles.”

“Our results show that silver nanoparticles in the biosolids, added at concentrations that would be expected, caused ecosystem-level impacts,” Colman said. “Specifically, the nanoparticles led to an increase in nitrous oxide fluxes, changes in microbial community composition, biomass, and extracellular enzyme activity, as well as species-specific effects on the above-ground vegetation.”

As previously noted, these two studies show just how complex the questions of risk and nanoparticles can become.  You can find out more about the Finish-Estonian study,

Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus by  Irina Blinova, Jukka Niskanen, Paula Kajankari, Liina Kanarbik, Aleksandr Käkinen, Heikki Tenhu, Olli-Pekka Penttinen, and Anne Kahru. Environmental Science and Pollution Research published November 11, 2012 online

The publisher offers an interesting option for this article. While it is behind a paywall, access is permitted through a temporary window if you want to preview a portion of the article that lies beyond the abstract.

Meanwhile here’s the article by the Duke researchers,

Low Concentrations of Silver Nanoparticles in Biosolids Cause Adverse Ecosystem Responses under Realistic Field Scenario by Benjamin P. Colman, Christina L. Arnaout, Sarah Anciaux, Claudia K. Gunsch, Michael F. Hochella Jr, Bojeong Kim, Gregory V. Lowry,  Bonnie M. McGill, Brian C. Reinsch, Curtis J. Richardson, Jason M. Unrine, Justin P. Wright, Liyan Yin, and Emily S. Bernhardt. PLoS ONE 2013; 8 (2): e57189 DOI: 10.1371/journal.pone.0057189

This article is open access as are all articles published by the Public Library of Science (PLoS) journals.

For anyone interested in the Duke University/CEINT mesocosm project, I made mention of it in an Aug. 15, 2011 posting.

American National Standards Institute’s (ANSI) nanotechnology standards panel to meet in Februrary 2013 and one more standard

The American National Standards Institute’s (ANSI) Nanotechnology Standards Panel (NSP) was scheduled to meet in Oct. 2012 but Hurricane Sandy, which hit the eastern part of the continent at that time, necessitated rescheduling to Feb. 4, 2013 as per the Dec. 20, 2012 posting on Thomas.net,

Originally scheduled for October 30, 2012, ANSI’s Nanotechnology Standards Panel meeting was postponed as a result of Hurricane Sandy and will now be held on February 4, 2013. Meeting will examine how current nanotechnology standards are being utilized and how standards activities meet existing stakeholder needs. Benefits of participating in nanotechnology standardization and the possibilities for greater collaboration between stakeholders in this area will also be discussed.

The Dec. 14, 2012 ANSI news release provides more details about the Feb. 4, 2012 meeting to be held in Washington, DC,

The half-day meeting will examine how current nanotechnology standards are being utilized and how standards activities meet existing stakeholder needs. The benefits for companies, organizations, and other groups to participate in nanotechnology standardization and the possibilities for greater collaboration between stakeholders in this area will also be discussed.

Formed in 2004, ANSI’s NSP serves as the cross-sector coordinating body for the facilitation of standards development in the area of nanotechnology. Shaun Clancy, Ph.D., the director of product regulatory services for the Evonik Degussa Corporation, and Ajit Jilavenkatesa, Ph.D., the senior standards policy advisor for the National Institute of Science and Technology (NIST) of the U.S. Department of Commerce (DoC), serve as the ANSI-NSP’s co-chairs.

… The ANSI-NSP works to provide a forum for standards developing organizations (SDOs), government entities, academia, and industry to identify needs and establish recommendations for the creation or updating of standards related to nanotechnology and nanomaterials. In addition, the ANSI-NSP solicits participation from nanotechnology-related groups that have not traditionally been involved in the voluntary consensus standards system, while also promoting cross-sector collaborative efforts.

Attendance at the February meeting is free. All attendees are required to register here for the meeting; individuals who registered for the October 2012 event must register again. [emphasis mine] For more information, visit the ANSI-NSP webpage or contact Heather Benko ([email protected]), ANSI senior manager, nanotechnology standardization activities.

Standardization is one of the topics highlighted in Michael Berger’s Dec. 20, 2012 Nanowerk Spotlight article about environmental health and safety and a high-throughput screening (HTS) platform developed at the University of California’s Center for Environmental Implications of Nanotechnology (CEIN) that can perform toxicity screening of 24 metal oxide nanoparticles simultaneously,

According to the team, the HTS platform that has been demonstrated in this study could easily be adapted to study other nanomaterials of interest. The capability of HTS would also allow researchers to analyze multiple samples at different concentrations, time points, as well as varying experimental parameters – all in one setup. The standardization of the whole screening process by this HTS platform also minimizes human intervention and errors during the experiment.

I guess it’s the season for standardization. Ho, ho, ho!