How Safe are Nanoparticles for Our Environment?

By Benedette Cuffari, M.Sc.Sep 8 2017

Almost every business or manufacturing industry has found their own unique application in the use of nanoparticles in their production of certain goods or services.

Such applications include, but are not limited to, applications in medicine, food, electronics, fuel and solar cells, batteries, aerospace technology, fuels, cleaner air and water, sensors, fabric and much more¹. There are many benefits associated with the use of nanoparticles in such various types of devices, of which are most often attributed to their ability to strengthen and reduce the weight of these devices, while simultaneously increasing their durability, reactivity and electrical conductivity².

While the addition of nanoparticles into its such applications exert obvious positive effects to its given industries, there are certain negative impacts of the use of nanotechnology that can occur within our environment. One of the most important properties that affects the way in which nanoparticles interact with our environment is due to their immensely large surface area.

Imagine you take a large boulder and determine its mass and surface area to volume ratio. Now you take a hammer and you smash the rock. The accumulated mass of the resulting smaller pieces remains the same, but the surface [area to volume [ratio] goes way up. Now take another hammer, and smash all of those small pieces into tiny pieces. They still have the same [combined] mass, but the surface area goes through the roof. That’s what nanoparticles are.

Ryan Otter, Biologist, the Middle Tennessee State University

As compared to their bulk counterparts, nanoparticles often exhibit much stronger and more reactive properties, which, in combination with their increased surface area, can also lead to much greater effects of the material upon any type of exposure to it. Another aspect of nanoparticles that allows for its variable toxicity to occur in the environment is due to the unpredictable shape and size of these materials.

This lack of uniformity among the sizes of nanoparticles not only causes difficulties in assessing how much of these particles are present within the environment, but it also prevents Researchers from having a precise analytical method to assess its potential toxicity in preliminary experiments.

A third way in which nanoparticles have the potential to cause environmental toxicity is attributed to the numerous interactions that these materials can have with other living or non-living organisms present within the environment. Such potential environmental processes that have the ability to influence the way in which nanomaterials cause damage include:

• Dissolution: The mixture of solid nanomaterials into a solvent.
• Precipitation/Sedimentation: The separation of nanomaterials following its presence within a solution.
• Speciation: The formation of nanomaterial variants that can react with each other.
• Binding to biotic or abiotic particles: Can include adhesion or sorption of nanomaterials within the environment.
• Transformation: A biological or chemical process that can occur following exposure to a nanomaterial.
• Agglomeration/Disagglomeration: The combination of nanomaterials with larger units, or further separation of the materials.
• Diffusion: The transportation of nanomaterials of which are present in an area of high concentration to an area of lower concentration⁴.

Aside from these properties, the fact that the surfaces of most engineered nanomaterials are coated with some type of additional material further complicates the way in which these materials are studied. Furthermore, the precise environmental conditions of the water, soil or atmosphere in which these particles are present in present their own variations in determining toxicity as a result to their specific acidity, concentration of existing minerals and salts, as well as other potential organic substances that could be present in these areas of the environment.   

In an effort to address this sensitive topic, Researchers from ETH Zurich’s Department of Chemistry and Applied Biosciences have recently established an effective method that has allowed for a better way to distinguish the different types of nanoparticles within the environment. By using a highly sensitive mass spectrometry technique known as spICP-TOF mass spectrometry, the Researchers analyzed various soil samples that naturally contain cerium particles, and then further mixed engineered cerium dioxide particles into the samples⁵.

With their mass spectrometry technique, the Researchers were able to successfully differentiate between the distinctive chemical fingerprints of both classes of particles. What they found was that the engineered nanoparticles were comprised of a single compound, whereas the natural particles were found to contain a number of additional chemical elements that were not seen in the artificial cerium⁵.

While the research completed by this team provides an insight into such a complicated field, there is still much uncertainty that surrounds the field of nanoecotoxicology. The intense variability of the potential ways in which nanoparticles interact with the environment have caused for a complete unpredictability to be attributed to its continuous presence. The need for a more structured and consistent database describing the precise mechanisms of toxicity of each of these engineered materials, as well as natural nanoparticles which also are not well understood, is urgent.

Image Credit:

Kateryna Kon/ Shutterstock.com

References:

1. "Nanotechnology Applications: A Variety of Uses." Understanding Nano. Web. http://www.understandingnano.com/nanotech-applications.html.
2. "Benefits and Applications." National Nanotechnology Initiative. Web. https://www.nano.gov/you/nanotechnology-benefits.
3. Ogden, Lesley Evans. "Nanoparticles in the Environment: Tiny Size, Large Consequences?" BioScience. Oxford University Press, 01 Mar. 2013. Web.
4. "Nanowerk Emerging Technology News." Nanowerk. Web. http://www.nanowerk.com/spotlight/spotid=25937.php.
5. "Nanoparticles Remain Unpredictable." ScienceDaily. ScienceDaily, 19 Apr. 2017. Web. https://www.sciencedaily.com/releases/2017/04/170419100841.htm.

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