Tag Archives: soil

Cleaning up disasters with Hokusai’s blue and cellulose nanofibers to clean up contaminated soil and water in Fukushima

The Great Wave off Kanagawa (Under a wave off Kanagawa”), also known as The Great Wave or simply The Wave, by Katsushika Hokusai – Metropolitan Museum of Art, online database: entry 45434, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2798407

I thought it might be a good idea to embed a copy of Hokusai’s Great Wave and the blue these scientists in Japan have used as their inspiration. (By the way, it seems these scientists collaborated with Mildred Dresselhaus who died at the age of 86, a few months after their paper was published. In honour of he and before the latest, here’s my Feb. 23, 2017 posting about the ‘Queen of Carbon’.)

Now onto more current news, from an Oct. 13, 2017 news item on Nanowerk (Note: A link has been removed),

By combining the same Prussian blue pigment used in the works of popular Edo-period artist Hokusai and cellulose nanofiber, a raw material of paper, a University of Tokyo research team succeeded in synthesizing compound nanoparticles, comprising organic and inorganic substances (Scientific Reports, “Cellulose nanofiber backboned Prussian blue nanoparticles as powerful adsorbents for the selective elimination of radioactive cesium”). This new class of organic/inorganic composite nanoparticles is able to selectively adsorb, or collect on the surface, radioactive cesium.

The team subsequently developed sponges from these nanoparticles that proved highly effective in decontaminating the water and soil in Fukushima Prefecture exposed to radioactivity following the nuclear accident there in March 2011.

I think these are the actual sponges not an artist’s impression,

Decontamination sponge spawned from current study
Cellulose nanofiber-Prussian blue compounds are permanently anchored in spongiform chambers (cells) in this decontamination sponge. It can thus be used as a powerful adsorbent for selectively eliminating radioactive cesium. © 2017 Sakata & Mori Laboratory.

An Oct. 13, 2017 University of Tokyo press release, which originated the news item, provides more detail about the sponges and the difficulties of remediating radioactive air and soil,

Removing radioactive materials such as cesium-134 and -137 from contaminated seawater or soil is not an easy job. First of all, a huge amount of similar substances with competing functions has to be removed from the area, an extremely difficult task. Prussian blue (ferric hexacyanoferrate) has a jungle gym-like colloidal structure, and the size of its single cubic orifice, or opening, is a near-perfect match to the size of cesium ions; therefore, it is prescribed as medication for patients exposed to radiation for selectively adsorbing cesium. However, as Prussian blue is highly attracted to water, recovering it becomes highly difficult once it is dissolved into the environment; for this reason, its use in the field for decontamination has been limited.

Taking a hint from the Prussian blue in Hokusai’s woodblock prints not losing their color even when getting wet from rain, the team led by Professor Ichiro Sakata and Project Professor Bunshi Fugetsu at the University of Tokyo’s Nanotechnology Innovation Research Unit at the Policy Alternatives Research Institute, and Project Researcher Adavan Kiliyankil Vipin at the Graduate School of Engineering developed an insoluble nanoparticle obtained from combining cellulose and Prussian blue—Hokusai had in fact formed a chemical bond in his handling of Prussian blue and paper (cellulose).

The scientists created this cellulose-Prussian blue combined nanoparticle by first preparing cellulose nanofibers using a process called TEMPO oxidization and securing ferric ions (III) onto them, then introduced a certain amount of hexacyanoferrate, which adhered to Prussian blue nanoparticles with a diameter ranging from 5–10 nanometers. The nanoparticles obtained in this way were highly resistant to water, and moreover, were capable of adsorbing 139 mg of radioactive cesium ion per gram.

Field studies on soil decontamination in Fukushima have been underway since last year. A highly effective approach has been to sow and allow plant seeds to germinate inside the sponge made from the nanoparticles, then getting the plants’ roots to take up cesium ions from the soil to the sponge. Water can significantly shorten decontamination times compared to soil, which usually requires extracting cesium from it with a solvent.

It has been more than six years since the radioactive fallout from a series of accidents at the Fukushima Daiichi nuclear power plant following the giant earthquake and tsunami in northeastern Japan. Decontamination with the cellulose nanofiber-Prussian blue compound can lead to new solutions for contamination in disaster-stricken areas.

“I was pondering about how Prussian blue immediately gets dissolved in water when I happened upon a Hokusai woodblock print, and how the indigo color remained firmly set in the paper, without bleeding, even after all these years,” reflects Fugetsu. He continues, “That revelation provided a clue for a solution.”

“The amount of research on cesium decontamination increased after the Chernobyl nuclear power plant accident, but a lot of the studies were limited to being academic and insufficient for practical application in Fukushima,” says Vipin. He adds, “Our research offers practical applications and has high potential for decontamination on an industrial scale not only in Fukushima but also in other cesium-contaminated areas.”

Here’s a link to and a citation for the paper,

Cellulose nanofiber backboned Prussian blue nanoparticles as powerful adsorbents for the selective elimination of radioactive cesium by Adavan Kiliyankil Vipin, Bunshi Fugetsu, Ichiro Sakata, Akira Isogai, Morinobu Endo, Mingda Li, & Mildred S. Dresselhaus. Scientific Reports 6, Article number: 37009 (2016) doi:10.1038/srep37009 Published online: 15 November 2016

This is open access.

US Dept. of Agriculture announces its nanotechnology research grants

I don’t always stumble across the US Department of Agriculture’s nanotechnology research grant announcements but I’m always grateful when I do as it’s good to find out about  nanotechnology research taking place in the agricultural sector. From a July 21, 2017 news item on Nanowerk,,

The U.S. Department of Agriculture’s (USDA) National Institute of Food and Agriculture (NIFA) today announced 13 grants totaling $4.6 million for research on the next generation of agricultural technologies and systems to meet the growing demand for food, fuel, and fiber. The grants are funded through NIFA’s Agriculture and Food Research Initiative (AFRI), authorized by the 2014 Farm Bill.

“Nanotechnology is being rapidly implemented in medicine, electronics, energy, and biotechnology, and it has huge potential to enhance the agricultural sector,” said NIFA Director Sonny Ramaswamy. “NIFA research investments can help spur nanotechnology-based improvements to ensure global nutritional security and prosperity in rural communities.”

A July 20, 2017 USDA news release, which originated the news item, lists this year’s grants and provides a brief description of a few of the newly and previously funded projects,

Fiscal year 2016 grants being announced include:

Nanotechnology for Agricultural and Food Systems

  • Kansas State University, Manhattan, Kansas, $450,200
  • Wichita State University, Wichita, Kansas, $340,000
  • University of Massachusetts, Amherst, Massachusetts, $444,550
  • University of Nevada, Las Vegas, Nevada,$150,000
  • North Dakota State University, Fargo, North Dakota, $149,000
  • Cornell University, Ithaca, New York, $455,000
  • Cornell University, Ithaca, New York, $450,200
  • Oregon State University, Corvallis, Oregon, $402,550
  • University of Pennsylvania, Philadelphia, Pennsylvania, $405,055
  • Gordon Research Conferences, West Kingston, Rhode Island, $45,000
  • The University of Tennessee,  Knoxville, Tennessee, $450,200
  • Utah State University, Logan, Utah, $450,200
  • The George Washington University, Washington, D.C., $450,200

Project details can be found at the NIFA website (link is external).

Among the grants, a University of Pennsylvania project will engineer cellulose nanomaterials [emphasis mine] with high toughness for potential use in building materials, automotive components, and consumer products. A University of Nevada-Las Vegas project will develop a rapid, sensitive test to detect Salmonella typhimurium to enhance food supply safety.

Previously funded grants include an Iowa State University project in which a low-cost and disposable biosensor made out of nanoparticle graphene that can detect pesticides in soil was developed. The biosensor also has the potential for use in the biomedical, environmental, and food safety fields. University of Minnesota (link is external) researchers created a sponge that uses nanotechnology to quickly absorb mercury, as well as bacterial and fungal microbes from polluted water. The sponge can be used on tap water, industrial wastewater, and in lakes. It converts contaminants into nontoxic waste that can be disposed in a landfill.

NIFA invests in and advances agricultural research, education, and extension and promotes transformative discoveries that solve societal challenges. NIFA support for the best and brightest scientists and extension personnel has resulted in user-inspired, groundbreaking discoveries that combat childhood obesity, improve and sustain rural economic growth, address water availability issues, increase food production, find new sources of energy, mitigate climate variability and ensure food safety. To learn more about NIFA’s impact on agricultural science, visit www.nifa.usda.gov/impacts, sign up for email updates (link is external) or follow us on Twitter @USDA_NIFA (link is external), #NIFAImpacts (link is external).

Given my interest in nanocellulose materials (Canada was/is a leader in the production of cellulose nanocrystals [CNC] but there has been little news about Canadian research into CNC applications), I used the NIFA link to access the table listing the grants and clicked on ‘brief’ in the View column in the University of Pennsylania row to find this description of the project,


NON-TECHNICAL SUMMARY: Cellulose nanofibrils (CNFs) are natural materials with exceptional mechanical properties that can be obtained from renewable plant-based resources. CNFs are stiff, strong, and lightweight, thus they are ideal for use in structural materials. In particular, there is a significant opportunity to use CNFs to realize polymer composites with improved toughness and resistance to fracture. The overall goal of this project is to establish an understanding of fracture toughness enhancement in polymer composites reinforced with CNFs. A key outcome of this work will be process – structure – fracture property relationships for CNF-reinforced composites. The knowledge developed in this project will enable a new class of tough CNF-reinforced composite materials with applications in areas such as building materials, automotive components, and consumer products.The composite materials that will be investigated are at the convergence of nanotechnology and bio-sourced material trends. Emerging nanocellulose technologies have the potential to move biomass materials into high value-added applications and entirely new markets.

It’s not the only nanocellulose material project being funded in this round, there’s this at North Dakota State University, from the NIFA ‘brief’ project description page,


NON-TECHNICAL SUMMARY: Synthetic polymers are quite vulnerable to fire.There are 2.4 million reported fires, resulting in 7.8 billion dollars of direct property loss, an estimated 30 billion dollars of indirect loss, 29,000 civilian injuries, 101,000 firefighter injuries and 6000 civilian fatalities annually in the U.S. There is an urgent need for a safe, potent, and reliable fire retardant (FR) system that can be used in commodity polymers to reduce their flammability and protect lives and properties. The goal of this project is to develop a novel, safe and biobased FR system using agricultural and woody biomass. The project is divided into three major tasks. The first is to manufacture zinc oxide (ZnO) coated cellulose nanoparticles and evaluate their morphological, chemical, structural and thermal characteristics. The second task will be to design and manufacture polymer composites containing nano sized zinc oxide and cellulose crystals. Finally the third task will be to test the fire retardancy and mechanical properties of the composites. Wbelieve that presence of zinc oxide and cellulose nanocrystals in polymers will limit the oxygen supply by charring, shielding the surface and cellulose nanocrystals will make composites strong. The outcome of this project will help in developing a safe, reliable and biobased fire retardant for consumer goods, automotive, building products and will help in saving human lives and property damage due to fire.

One day, I hope to hear about Canadian research into applications for nanocellulose materials. (fingers crossed for good luck)

Nanomaterials and UV (ultraviolet) light for environmental cleanups

I think this is the first time I’ve seen anything about a technology that removes toxic materials from both water and soil; it’s usually one or the other. A July 22, 2015 news item on Nanowerk makes the announcement (Note: A link has been removed),

Many human-made pollutants in the environment resist degradation through natural processes, and disrupt hormonal and other systems in mammals and other animals. Removing these toxic materials — which include pesticides and endocrine disruptors such as bisphenol A (BPA) — with existing methods is often expensive and time-consuming.

In a new paper published this week in Nature Communications (“Nanoparticles with photoinduced precipitation for the extraction of pollutants from water and soil”), researchers from MIT [Massachusetts Institute of Technology] and the Federal University of Goiás in Brazil demonstrate a novel method for using nanoparticles and ultraviolet (UV) light to quickly isolate and extract a variety of contaminants from soil and water.

A July 21, 2015 MIT news release by Jonathan Mingle, which originated the news item, describes the inspiration and the research in more detail,

Ferdinand Brandl and Nicolas Bertrand, the two lead authors, are former postdocs in the laboratory of Robert Langer, the David H. Koch Institute Professor at MIT’s Koch Institute for Integrative Cancer Research. (Eliana Martins Lima, of the Federal University of Goiás, is the other co-author.) Both Brandl and Bertrand are trained as pharmacists, and describe their discovery as a happy accident: They initially sought to develop nanoparticles that could be used to deliver drugs to cancer cells.

Brandl had previously synthesized polymers that could be cleaved apart by exposure to UV light. But he and Bertrand came to question their suitability for drug delivery, since UV light can be damaging to tissue and cells, and doesn’t penetrate through the skin. When they learned that UV light was used to disinfect water in certain treatment plants, they began to ask a different question.

“We thought if they are already using UV light, maybe they could use our particles as well,” Brandl says. “Then we came up with the idea to use our particles to remove toxic chemicals, pollutants, or hormones from water, because we saw that the particles aggregate once you irradiate them with UV light.”

A trap for ‘water-fearing’ pollution

The researchers synthesized polymers from polyethylene glycol, a widely used compound found in laxatives, toothpaste, and eye drops and approved by the Food and Drug Administration as a food additive, and polylactic acid, a biodegradable plastic used in compostable cups and glassware.

Nanoparticles made from these polymers have a hydrophobic core and a hydrophilic shell. Due to molecular-scale forces, in a solution hydrophobic pollutant molecules move toward the hydrophobic nanoparticles, and adsorb onto their surface, where they effectively become “trapped.” This same phenomenon is at work when spaghetti sauce stains the surface of plastic containers, turning them red: In that case, both the plastic and the oil-based sauce are hydrophobic and interact together.

If left alone, these nanomaterials would remain suspended and dispersed evenly in water. But when exposed to UV light, the stabilizing outer shell of the particles is shed, and — now “enriched” by the pollutants — they form larger aggregates that can then be removed through filtration, sedimentation, or other methods.

The researchers used the method to extract phthalates, hormone-disrupting chemicals used to soften plastics, from wastewater; BPA, another endocrine-disrupting synthetic compound widely used in plastic bottles and other resinous consumer goods, from thermal printing paper samples; and polycyclic aromatic hydrocarbons, carcinogenic compounds formed from incomplete combustion of fuels, from contaminated soil.

The process is irreversible and the polymers are biodegradable, minimizing the risks of leaving toxic secondary products to persist in, say, a body of water. “Once they switch to this macro situation where they’re big clumps,” Bertrand says, “you won’t be able to bring them back to the nano state again.”

The fundamental breakthrough, according to the researchers, was confirming that small molecules do indeed adsorb passively onto the surface of nanoparticles.

“To the best of our knowledge, it is the first time that the interactions of small molecules with pre-formed nanoparticles can be directly measured,” they write in Nature Communications.

Nano cleansing

Even more exciting, they say, is the wide range of potential uses, from environmental remediation to medical analysis.

The polymers are synthesized at room temperature, and don’t need to be specially prepared to target specific compounds; they are broadly applicable to all kinds of hydrophobic chemicals and molecules.

“The interactions we exploit to remove the pollutants are non-specific,” Brandl says. “We can remove hormones, BPA, and pesticides that are all present in the same sample, and we can do this in one step.”

And the nanoparticles’ high surface-area-to-volume ratio means that only a small amount is needed to remove a relatively large quantity of pollutants. The technique could thus offer potential for the cost-effective cleanup of contaminated water and soil on a wider scale.

“From the applied perspective, we showed in a system that the adsorption of small molecules on the surface of the nanoparticles can be used for extraction of any kind,” Bertrand says. “It opens the door for many other applications down the line.”

This approach could possibly be further developed, he speculates, to replace the widespread use of organic solvents for everything from decaffeinating coffee to making paint thinners. Bertrand cites DDT, banned for use as a pesticide in the U.S. since 1972 but still widely used in other parts of the world, as another example of a persistent pollutant that could potentially be remediated using these nanomaterials. “And for analytical applications where you don’t need as much volume to purify or concentrate, this might be interesting,” Bertrand says, offering the example of a cheap testing kit for urine analysis of medical patients.

The study also suggests the broader potential for adapting nanoscale drug-delivery techniques developed for use in environmental remediation.

“That we can apply some of the highly sophisticated, high-precision tools developed for the pharmaceutical industry, and now look at the use of these technologies in broader terms, is phenomenal,” says Frank Gu, an assistant professor of chemical engineering at the University of Waterloo in Canada, and an expert in nanoengineering for health care and medical applications.

“When you think about field deployment, that’s far down the road, but this paper offers a really exciting opportunity to crack a problem that is persistently present,” says Gu, who was not involved in the research. “If you take the normal conventional civil engineering or chemical engineering approach to treating it, it just won’t touch it. That’s where the most exciting part is.”

The researchers have made this illustration of their work available,

Nanoparticles that lose their stability upon irradiation with light have been designed to extract endocrine disruptors, pesticides, and other contaminants from water and soils. The system exploits the large surface-to-volume ratio of nanoparticles, while the photoinduced precipitation ensures nanomaterials are not released in the environment. Image: Nicolas Bertrand Courtesy: MIT

Nanoparticles that lose their stability upon irradiation with light have been designed to extract endocrine disruptors, pesticides, and other contaminants from water and soils. The system exploits the large surface-to-volume ratio of nanoparticles, while the photoinduced precipitation ensures nanomaterials are not released in the environment.
Image: Nicolas Bertrand Courtesy: MIT

Here’s a link to and a citation for the paper,

Nanoparticles with photoinduced precipitation for the extraction of pollutants from water and soil by Ferdinand Brandl, Nicolas Bertrand, Eliana Martins Lima & Robert Langer. Nature Communications 6, Article number: 7765 doi:10.1038/ncomms8765 Published 21 July 2015

This paper is open access.

Kavli nanoscience and microbiomes

It’s been a while since I’ve mentioned the Kavli Foundation, which is dedicated to “advancing basic science for humanity.” On this occasion,  there’s a Feb. 12, 2015 news item on Nanowerk featuring a Kavli Foundation discussion about nanoscience and microbiomes,

Microbiomes, communities of one-celled organisms, are everywhere in nature. They play important roles in health and agriculture, yet we know surprisingly little about them. Nanoscience might help.

In a far-ranging discussion, two top researchers spoke with the Kavli Foundation about how nanoscience can help us understand and manipulate natural microbiomes.

Microbiomes are communities of bacteria, fungi, protozoa, algae, other one-celled microbes, and viruses that interact with one another in complex ways. These ecosystems are enormously complex. A few grams of soil or marine sediment might contain as many as several hundred thousand different species of microbes.

“There are all these amazing chemistries that microbes perform that can do really wonderful things for humanity, like providing new antibiotics and nutrients for crops. It’s pretty much an unlimited resource of novelty and chemistry—if we can develop improved tools to tap into it,” said Eoin Brodie, a staff scientist in Lawrence Berkeley National Laboratory’s Ecology Department.

In the past, researchers have sought to understand these communities by growing different microbes in cultures and observing their behaviors. Yet only a small fraction of these microorganisms grow in pure cultures.

Nanoscience could provide new ways to unravel these complex ecosystems, according to Jack Gilbert, a principle investigator at Argonne National Laboratory’s Biosciences Division.

You can continue reading either on Nanowerk or here on the Kavli website where you’ll find the Kavli Foundation is having a series of conversations about microbiomes, which you may want to check out. This conversation with Brodie and Gilbert seems to be in aid of an upcoming Google Hangout,

Spotlight Live: Thinking Smaller – How Nanoscience Can Help Us Understand Nature’s Many Microbiomes
Wednesday, March 4 – 11:00 am PST

Join us here on March 4 for a live Google Hangout with Eoin Brodie and Jack A. Gilbert. Questions can be submitted by email or via Twitter with the hashtag: #KavliLive. For updates, follow The Kavli Foundation on Twitter and Facebook.

Food and nanotechnology (as per Popular Mechanics) and zinc oxide nanoparticles in soil (as per North Dakota State University)

I wouldn’t expect to find an article about food in a magazine titled Popular Mechanics but there it is, a Feb. 19,2014 article by Christina Ortiz (Note: A link has been removed),

For a little more than a decade, the food industry has been using nanotechnology to change the way we grow and maintain our food. The grocery chain Albertsons currently has a list of nanotech-touched foods in its home brand, ranging from cookies to cheese blends.

Nanotechnology use in food has real advantages: The technology gives producers the power to control how food looks, tastes, and even how long it lasts.

Looks Good and Good for You?

The most commonly used nanoparticle in foods is titanium dioxide. It’s used to make foods such as yogurt and coconut flakes look as white as possible, provide opacity to other food colorings, and prevent ingredients from caking up. Nanotech isn’t just about aesthetics, however. The biggest potential use for this method involves improving the nutritional value of foods.

Nano additives can enhance or prevent the absorption of certain nutrients. In an email interview with Popular Mechanics, Jonathan Brown, a research fellow at the University of Minnesota, says this method could be used to make mayonnaise less fattening by replacing fat molecules with water droplets.

I did check out US grocer, Albertson’s list of ‘nanofoods’, which they provide and discovered that it’s an undated listing on the Project of Emerging Nanotechnologies’ Consumer Products Inventory (CPI). The inventory has been revived recently after lying moribund for a few years (my Oct. 28, 2013 posting describes the fall and rise) and I believe that this 2013 CPI incarnation includes some oversight and analysis of the claims made, which the earlier version did not include. Given that the Albertson’s list is undated it’s difficult to assess the accuracy of the claims regarding the foodstuffs.

If you haven’t read about nanotechnology and food before, the Ortiz article provides a relatively even-handed primer although it does end on a cautionary note. In any event, it was interesting to get a bit of information about the process of ‘nanofood’ regulation in the US and other jurisdictions (from the Ortiz article),

Aside from requiring manufacturers to provide proof that nanotechnology foods are safe, the FDA has yet to implement specific testing of its own. But many countries are researching ways to balance innovation and regulation in this market. In 2012 the European Food Safety Authority (EFSA) released an annual risk assessment report outlining how the European Union is addressing the issue of nanotech in food. In Canada the Food Directorate “is taking a case-by-case approach to the safety assessment of food products containing or using nanomaterials.”

I featured the FDA’s efforts regarding regulation and ‘nanofood’ in an April 23, 2012 posting,

It looks to me like this [FDA’s draft guidance for ‘nanofoods’] is an attempt to develop a relationship where the industry players in the food industry to police their nanotechnology initiatives with the onus being on industry to communicate with the regulators in a continuous process, if not at the research stage certainly at the production stage.

At least one of the primary issues with any emerging technology revolves around the question of risk. Do we stop all manufacturing and development of nanotechnology-enabled food products until we’ve done the research? That question assumes that taking any risks is not worth the currently perceived benefits. The corresponding question, do we move forward and hope for the best? does get expressed perhaps not quite so baldly; I have seen material which suggests that research into risks needlessly hampers progress.

After reading on this topic for five or so years, my sense is that most people are prepared to combine the two approaches, i.e., move forward while researching possible risks. The actual conflicts seem to centre around these questions, how quickly do we move forward; how much research do we need; and what is an acceptable level of risk?

On the topic of researching the impact that nanoparticles might have on plants (food or otherwise), a January 24, 2013 North Dakota State University (NDSU) news release highlights a student researcher’s work on soil, plants, and zinc oxide nanoparticles,

NDSU senior Hannah Passolt is working on a project that is venturing into a very young field of research. The study about how crops’ roots absorb a microscopic nutrient might be described as being ahead of the cutting-edge.

In a laboratory of NDSU’s Wet Ecosystem Research Group, in collaboration with plant sciences, Passolt is exploring how two varieties of wheat take up extremely tiny pieces of zinc, called nanoparticles, from the soil.

As a point of reference, the particles Passolt is examining are measured at below 30 nanometers. A nanometer is 1 billionth of a meter.

“It’s the mystery of nanoparticles that is fascinating to me,” explained the zoology major from Fargo. “The behavior of nanoparticles in the environment is largely unknown as it is a very new, exciting science. This type of project has never been done before.”

In Passolt’s research project, plants supplied by NDSU wheat breeders are grown in a hydroponic solution, with different amounts of zinc oxide nanoparticles introduced into the solution.

Compared to naturally occurring zinc, engineered zinc nanoparticles can have very different properties. They can be highly reactive, meaning they can injure cells and tissues, and may cause genetic damage. The plants are carefully observed for any changes in growth rate and appearance. When the plants are harvested, researchers will analyze them for actual zinc content.

“Zinc is essential for a plant’s development. However, in excess, it can be harmful,” Passolt said. “In one of my experiments, we are using low and high levels of zinc, and the high concentrations are showing detrimental effects. However, we will have to analyze the plants for zinc concentrations to see if there have been any effects from the zinc nanoparticles.”

Passolt has conducted undergraduate research with the Wet Ecosystem Research Group for the past two years. She said working side-by-side with Donna Jacob, research assistant professor of biological sciences; Marinus Otte; professor of biological sciences; and Mohamed Mergoum, professor of plant sciences, has proven to be challenging, invigorating and rewarding.

“I’ve gained an incredible skill set – my research experience has built upon itself. I’ve gotten to the point where I have a pretty big role in an important study. To me, that is invaluable,” Passolt said. “To put effort into something that goes for the greater good of science is a very important lesson to learn.”

According to Jacob, Passolt volunteered two years ago, and she has since become an important member of the group. She has assisted graduate students and worked on her own small project, the results of which she presented at regional and international scientific conferences. “We offered her this large, complex experiment, and she’s really taken charge,” Jacob said, noting Passolt assisted with the project’s design, handled care of the plants and applied the treatments. When the project is completed, Passolt will publish a peer-reviewed scientific article.

“There is nothing like working on your own experiment to fully understand science,” Jacob said. “Since coming to NDSU in 2006, the Wet Ecosystem Research Group has worked with more than 50 undergraduates, possible only because of significant support from the North Dakota IDeA Networks of Biomedical Research Excellence program, known as INBRE, of the NIH National Center for Research Resources.”

Jacob said seven undergraduate students from the lab have worked on their own research projects and presented their work at conferences. Two articles, so far, have been published by undergraduate co-authors. “I believe the students gain valuable experience and an understanding of what scientists really do during fieldwork and in the laboratory,” Jacob said. “They see it is vastly different from book learning, and that scientists use creativity and ingenuity daily. I hope they come away from their experience with some excitement about research, in addition to a better resume.”

Passolt anticipates the results of her work could be used in a broader view of our ecosystem. She notes zinc nanoparticles are an often-used ingredient in such products as lotions, sunscreens and certain drug delivery systems. “Zinc nanoparticles are being introduced into the environment,” she said. “It gets to plants at some point, so we want to see if zinc nanoparticles have a positive or negative effect, or no effect at all.”

Researching nanoparticles the effects they might have on the environment and on health is a complex process as there are many types of nanoparticles some of which have been engineered and some of which occur naturally, silver nanoparticles being a prime example of both engineered and naturally occurring nanoparticles. (As well, the risks may lie more with interactions between nanomaterials.) For an example of research, which seems similar to the NDSU effort, there’s this open access research article,

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

One last comment, the Wet Ecosystem Research Group (WERG) mentioned in the news release about Passolt has an interesting history (from the homepage; Note: Links have been removed),

Marinus Otte and Donna Jacob brought WERG to the Department of Biological Sciences in the Fall of 2006.  Prior to that, the research group had been going strong at University College Dublin, Ireland, since 1992.

The aims for the research group are to train graduate and undergraduate students in scientific research, particularly wetlands, plants, biogeochemistry, watershed ecology and metals in the environment.  WERG research  covers a wide range of scales, from microscopic (e.g. biogeochemical processes in the rhizosphere of plants) to landscape (e.g. chemical and ecological connectivity between prairie potholes across North Dakota).  Regardless of the scale, the central theme is biogeochemistry and the interactions between multiple elements in wet environments.

The group works to collaborate with a variety of researchers, including soil scientists, geologists, environmental engineers, microbiologists, as well as with groups underpinning management of natural resources, such the Minnesota Department of Natural Resources, the Department of Natural Resources of Red Lake Indian Reservation, and the North Dakota Department of Health, Division of Water Quality.

Currently, WERG has several projects, mostly in North Dakota and Minnesota.  Otte and Jacob are also Co-directors of the North Dakota INBRE Metal Analysis Core, providing laboratory facilities and mentoring for researchers in undergraduate colleges throughout the state. Otte and Jacob are also members of the Upper Midwest Aerospace Consortium.

Toxicity, nanoparticles, soil, and Europe’s NANO-ECOTOXICITY Project

I have featured pieces on nanoparticles, toxicity, and soil in the past (this Aug. 15, 2011 posting about Duke University’s mesocosm project is probably the most relevant) but this study is the first one I’ve seen focusing on earthworms. From the Sept. 23, 2013 news item on Nanowerk (Note: A link has been removed),

From the clothes and make-up we wear to the electronic devices we use every day, nanotechnology is becoming ubiquitous. But while industry has mastered the production of such materials, little is known about their fate once their service life comes to an end. The NANO-ECOTOXICITY project looked into their impact on soil organisms.

The Sept. 23, 2013 CORDIS (European Commission Community Research and Development Information Service) news release, which originated the new item, offers a Q&A (Question and Answer) with the project research leader,

Dr Maria Diez-Ortiz, research leader of the NANO-ECOTOXICITY project, tells us about her research findings and how she expects them to help increase knowledge and shape tools allowing for standard environmental hazard and risk-assessment methodologies.

What is the background of the NANO-ECOTOXICITY project?

Nanotechnology is based on the idea that, by engineering the size and shape of materials at the scale of atoms, i.e. nanometres (nm), distinct optical, electronic, or magnetic properties can be tuned to produce novel properties of commercial value. However, there is an obvious concern that such novel properties may also lead to novel behaviour when interacting with biological organisms, and thus to potentially novel toxic effects.

Since nanoparticles (NPs) are similar in size to viruses, their uptake by and transport through tissues are based on mechanisms distinct from those of molecular uptake and transport. Therefore, there is concern that standard toxicological tests may not be applicable or reliable in relation to NPs, hence compromising current risk-assessment procedures.

The majority of research on nano-safety in the environment has so far focused on the aquatic environment. Current research on environmental fate, however, indicates that soils will become the biggest environmental sink for nanoparticles. Following their entry into liquid waste streams, nanoparticles will pass through wastewater-treatment. processes, ending up in waste sludge which may accumulate in the agricultural land where this sludge is often applied.

What are the main objectives of the project?

This project deals with the toxicokinetics – that is, the rate at which a chemical enters a body and affects it – of metal nanoparticles coming into contact with soil-dwelling organisms. The aim is to determine NPs’ fate and effects in terrestrial ecosystems by means of case studies with zinc oxide and silver NPs, which represent different fate kinetics.

The project’s main objectives are to assess the toxicity of metal nanoparticles in soils in the short and long term; the main route of exposure for earthworms and whether it differs from those of ionic metals; and, finally, the influence of the exposure media on metal nanoparticle toxicity.

What is new or innovative about the project and the way it is addressing these issues?

We have been running a long-term study where soils with AgNP [silver nanoparticles] were stored and left to age for up to a year; their toxicity was tested at the start and after three, seven and 12 months of ageing. The results showed that silver toxicity increased over time, meaning that short-term standard toxicity tests may underestimate the environmental risk of silver nanoparticles.

In parallel, we found that organisms exposed to silver nanoparticles in short-term studies accumulated higher silver concentrations than organisms that were exposed to the same mass concentration of ionic silver. However, these NP exposed organisms actually suffered lower toxic effects. This observation contradicts the prevailing assumption in toxicology that the internalised concentration is directly related to chemical concentration at the target site and hence to its toxicity. This observation creates a new paradigm for nano-ecotoxicology.

What is not yet known is whether the accumulated NP metal may in the longer-term ultimately become toxic (e.g. through dissolution and ion release) in cells and tissues where AgNPs may be stored. Should this occur, the high concentrations accumulated may ultimately result in greater long-term toxicity for NPs than for ionic forms. This may reveal these accumulated NPs as internalised ‘time bombs’ relevant to long-term effects and toxicity.

However, it has to be borne in mind that the redicted environmental concentrations resulting from current use of nanoparticles (e.g. results from EU projects like NANOFATE2) are many times smaller than those used in these studies, meaning that such accumulations of nanoparticle-related silver are unlikely to occur in the environment or, ultimately, in humans.

What difficulties did you encounter and how did you solve them?

The main problems encountered relate to the tracking of nanoparticles inside the tissues and soils, as both are complex matrices. The analysis of the particles is a challenge in itself, even when in water, but to get information about their state in these matrices often requires unrealistic exposure concentrations (due to low detection limits of the highly specialised techniques used for analysis) or extraction of the particles from the matrices, which could potentially change the state of the particles.

In this project, I travelled to University of Kentucky to work with Jason Unrine and used gentle water-based extractions of soil samples immediately before analysing them using ‘Field-flow fractionation’ and ‘Inductively coupled plasma mass spectrometry’ to identify the state of nanoparticles in my aged soils.

To look at what form (speciation) of silver and zinc from the nanoparticle exposures could be found inside worms I collaborated with NANOFATE researchers at Cardiff University who fixed and thinly sectioned the worm tissues. I was lucky to be given the time to use specialist facilities like the UK’s Diamond Light Source synchrotron to investigate where and in what form the metals and potential nanoparticles could be found in these tissues.

The main challenge is that as soon as you take nanoparticles out of the manufacturers’ bottle they start changing, particularly when put into environments likes natural soils and waters, or even organisms. Therefore a lot of characterisation is needed during exposure to establish the state of the nanoparticles the organisms have been exposed to and how fast they are changing from pristine particles to dissolved ions, or particles with completely different surfaces.

Technical solutions to characterisation have been found during this short project, but this will remain a logistical challenge for many years to come as the analysis equipment is still very specialised and expensive and therefore not generally available.

What are the concrete results from the research so far?

The project has helped us draw various conclusions regarding the impact of NPs on the environment and how to assess them. First, we now know that soil acidity, or pH, influences the dissolution and toxicity of ZnO nanoparticles [zinc oxide].

Then, we found that toxicity of silver nanoparticles’ increases over time and that the particles’ coating affects their toxicity to soil invertebrates.

As previously mentioned, earthworms exposed to silver nanoparticles for 28 days accumulated higher silver concentrations than earthworms exposed to silver ions, without the excess silver from the nanoparticles having a toxic effect. [emphasis mine] Moreover, soil ingestion was identified as the main route of exposure to AgNP and ZnONP in earthworms.

How can industry and decision-makers ensure that nanomaterials do not impact our environment?

We hope that this project, and the larger EU project NANOFATE to which it is linked, will provide knowledge and tools enabling standard environmental-hazard and risk-assessment methodologies to be applied to engineered nanoparticles (ENPs) with just a few judicious modifications. The current systems and protocols for chemical risk assessment have been developed over decades, and where no novel toxic mechanisms exist, our results tend to say that nano fits in as long as we measure the right things and characterise realistic exposures properly.

Our research aims to determine the minimum methodological tweaks needed. So far everything indicates that the potential benefits from nanotechnology can be realised and managed safely alongside other chemicals. While we are fairly confident at this stage that ENPs impose no greater acute effects on important biological parameters – like reproduction – than their ionic forms, the NANO-ECOTOXICITY results demonstrate that we have some way to go before we can state loud and clear that we do not believe there is any novel low-level or long-term effect.

As for all chemicals, proving such a negative is impossible using short-term tests. We think the final conclusions by industry and regulators on safe use of nanoparticles should and will have to be made according to a ‘weight of evidence’ approach – proving there is a gap between predicted likely exposure levels and those levels seen to cause any effects or accumulations within ecosystem species.

What are the next topics for your research?

This project has finished but the next step for any other funding opportunity would be to address increasingly environmentally relevant exposure scenarios by analysing how nanoparticles modify in the environment and interact with living tissues and organisms at different trophic levels. I would like to investigate nanoparticle transformation and interactions in living tissues. To date, the studies that have identified this ‘excess’ accumulation of non-toxic metal loads in nanoparticleexposed organisms have only been short term.

Apart from the obviously increased food-chain transfer potential, is also not known whether, over the longer term, the accumulated NP-derived metal ultimately becomes toxic when present in tissues and cells. Such transformation and release of metal ions within tissues may ultimately result in greater longterm toxicity for NPs than for ionic forms.

Furthermore, I want to test exposures in a functioning model ecosystem including interspecific interactions and trophic transfer. Since interactions between biota and nanoparticles are relevant in natural soil systems, caution is needed when attempting to predict the ecological consequences of nanoparticles based on laboratory assays conducted with only a single species. In the presence of the full complement of biological components of soil systems, complex NPs may follow a range of pathways in which coatings may be removed and replaced with exudate materials. Studies to quantify the nature of these interactions are therefore needed to identify the fate, bioavailability and toxicity of realistic ‘non-pristine’ forms of NPs present in real soil environments.

New to me was the material about ageing silver nanoparticles and their increased toxicity over time. While this is an interesting piece of information it’s not necessarily all that useful. It seems even with their increased uptake compared to silver ions, silver nanoparticles (Diez-Ortiz doesn’t indicate whether or not * they tested variously aged silver nanoparticles) did not have toxic effects on the earthworms tested.

The NANO-ECOTOXICITY website doesn’t appear to exist anymore but you can find the NANOFATE (Nanoparticle Fate Assessment and Toxicity in the Environment) website here.

* ‘not’ removed to clarify meaning, Oct. 9, 2013. (Note: I had on Oct. 8, 2013 removed ‘not’ in a second place from the sentence in an attempt t o clarify the meaning and ended up not making any sense at all.) Please read Maria Diez-Ortiz in the Comments, as she clarifies matters in a way I could never hope to.

Using microwaves to test for carbon nanotube toxicity in soil

It’s been a while since I’ve mentioned soil or environmental testing for this this Oct. 19, 2012 news item by Karen Slyker on physorg.com, which highlights some research on environmental testing of carbon nanotubes, lets me redress the situation,

Industrial uses are growing, as are concerns that these novel nanomaterials may have negative or unintended effects on organisms and the environment. With this in mind, environmental toxicologists at Texas Tech are exploring the fate of CNTs in biological environments and their ability to accumulate in soil, plants or other organisms.

One recurring question has slowed these studies: How can anyone be certain the tiny CNTs are present in the given sample?

“It’s like a needle in a haystack,” Green said [Micah Green, assistant professor of chemical engineering]. “How can you prove the effects of the needle, if you’re not sure that it’s really in there?”

The impetus for the work initially began with a conversation between Green and Jaclyn Cañas, associate professor of environmental toxicology at The Institute for Environmental and Human Health at Texas Tech. Cañas described the problem of detecting CNTs in crop samples. Green suggested that exposing samples to microwaves could reveal the presence of even trace quantities of nanotubes.

The Texas Technical University Oct. 19, 2012 news release (which originated the news item) provides more detail about the approach,

CNTs have the unusual property of evolving extreme amounts of heat upon exposure to microwaves, much more so than typical materials. In fact, nanotube powder will quickly and spontaneously ignite if placed in a conventional kitchen microwave. Green’s idea was to expose the sample to low-power microwaves and measure the resulting increase in temperature.

Mohammad Saed, an associate professor in electrical and computer engineering, joined the team to contribute his expertise in the area of microwave physics.

Together, the three research groups successfully built a testing apparatus and proved the concepts that microwave-based heating can quantify CNT loading inside a plant sample.

The team has refined its testing protocols and extended the scope from soil testing only to including earthworms,

Continued development of the device led to a double-blind test, where a student was given samples of a specified CNT loading but was not told what the concentration was. Graduate student Fahmida Irin was principally responsible for applying the method. The double-blind test successfully duplicated the true values, and was then applied to studying the uptake of nanotubes into alfalfa plant roots grown in soil spiked with nanotubes.

“Since we started the method, we have started collaborating with other groups as well to look at the presence of nanotubes in organisms like earthworms,” Green said.

The method was recently published in a paper entitled “Detection of carbon nanotubes in biological samples through microwave-induced heating” by Irin et al. in the journal Carbon.

I’m not quite sure how to take this research. They do mention that nanotube powder will ignite in a kitchen microwave. Here’s hoping the researchers have designed an apparatus that cannot accidentally ignite carbon nanotubes in soil, plants, or earthworms.