The best of EcoWatch, right in your inbox. Sign up for our email newsletter!
Study Finds Common Man-Made Nanoparticles Can Damage Plant DNA
Researchers at the National Institute of Standards and Technology (NIST) and the University of Massachusetts Amherst (UMass) have provided the first evidence that engineered nanoparticles are able to accumulate within plants and damage their DNA. In a recent paper,1 the team led by NIST chemist Bryant C. Nelson showed that under laboratory conditions, cupric oxide nanoparticles have the capacity to enter plant root cells and generate many mutagenic DNA base lesions.
The team tested the man-made, ultrafine particles between 1 and 100 nanometers in size on a human food crop, the radish, and two species of common groundcovers used by grazing animals, perennial and annual ryegrass. This research is part of NIST's work to help characterize the potential environmental, health and safety (EHS) risks of nanomaterials, and develop methods for identifying and measuring them.
Cupric oxide (also known as copper (II) oxide or CuO) is a compound that has been used for many years as a pigment for coloring glass and ceramics, as a polish for optics, and as a catalyst in the manufacture of rayon. Cupric oxide also is a strong conductor of electric current, a property enhanced at the nanoscale level, which makes the nanoparticle form useful to semiconductor manufacturers.
Because cupric oxide is an oxidizing agent—a reactive chemical that removes electrons from other compounds—it may pose a risk. Oxidation caused by metal oxides has been shown to induce DNA damage in certain organisms. What Nelson and his colleagues wanted to learn was whether nanosizing cupric oxide made the generation and accumulation of DNA lesions more or less likely in plants. If the former, the researchers also wanted to find out if nanosizing had any substantial effects on plant growth and health.
To obtain the answers, the NIST/UMass researchers first exposed radishes and the two ryegrasses to both cupric oxide nanoparticles and larger sized cupric oxide particles (bigger than 100 nanometers) as well as to simple copper ions. They then used a pair of highly sensitive spectrographic techniques2 to evaluate the formation and accumulation of DNA base lesions and to determine if and how much copper was taken up by the plants.
For the radishes, twice as many lesions were induced in plants exposed to nanoparticles as were in those exposed to the larger particles. Additionally, the cellular uptake of copper from the nanoparticles was significantly greater than the uptake of copper from the larger particles. The DNA damage profiles for the ryegrasses differed from the radish profiles, indicating that nanoparticle-induced DNA damage is dependent on the plant species and on the nanoparticle concentration.
Finally, the researchers showed that cupric oxide nanoparticles had a significant effect on growth, stunting the development of both roots and shoots in all three plant species tested. The nanoparticle concentrations used in this study were higher than those likely to be encountered by plants under a typical soil exposure scenario.
"To our knowledge, this is first evidence that there could be a 'nano-based effect' for cupric oxide in the environment where size plays a role in the increased generation and accumulation of numerous mutagenic DNA lesions in plants," Nelson says.
Next up for Nelson and his colleagues is a similar study looking at the impact of titanium dioxide nanoparticles—such as those used in many sunscreens—on rice plants.
For more information, click here.
1. D.H. Atha, H. Wang, E.J. Petersen, D. Cleveland, R.D. Holbrook, P. Jaruga, M. Dizdaroglu, B. Xing and B.C. Nelson. Copper oxide nanoparticle mediated DNA damage in terrestrial plant models. Environmental Science and Technology, Vol. 46 (3): pages 1819-1827 (2012), DOI: 10.1021/es202660k.
2. Gas chromatography–mass spectrometry (GC-MS) to detect base lesions and inductively coupled plasma mass spectrometry (ICP-MS) to measure copper uptake.
EcoWatch Daily Newsletter
The world awakened to the hole in the ozone layer in 1985, which scientists attributed it to ozone depleting substances. Two years later, in Montreal, the world agreed to ban the halogen compounds causing the massive hole over Antarctica. Research now shows that those chemicals didn't just cut a hole in the ozone layer, they also warmed up the Arctic.
Formosa Plant May Still Be Releasing Plastic Pollution in Texas After $50M Settlement, Activists Find
On the afternoon of Jan. 15, activist Diane Wilson kicked off a San Antonio Estuary Waterkeeper meeting on the side of the road across from a Formosa plastics manufacturing plant in Point Comfort, Texas.
After Wilson and the waterkeeper successfully sued Formosa in 2017, the company agreed to no longer release even one of the tiny plastic pellets known as nurdles into the region's waterways. The group of volunteers had assembled that day to check whether the plant was still discharging these raw materials of plastics manufacturing.
Malaysia Sends Plastic Waste Back to 13 Wealthy Countries, Says It Won’t Be 'the Rubbish Dump of the World'
The Southeast Asian country Malaysia has sent 150 shipping containers packed with plastic waste back to 13 wealthy countries, putting the world on notice that it will not be the world's garbage dump, as CNN reported. The countries receiving their trash back include the United States, the United Kingdom, France and Canada.