Stories tagged titanium dioxide


Professor Richard Handy and his team of scientists at Plymouth University in the UK have discovered that nanoparticles of titanium dioxide are causing holes to form (you can call them vacuoles if you want to be fancy), and nerve cells to die, in the brains of living fish. Titanium Dioxide
Titanium DioxideCourtesy Wikimedia Commons

“Gee, that sounds bad,” you might think. “But what does that have to do with me? I can’t say I’ve ever purchased a box of titanium dioxide at the grocery store.” Nope, you haven’t. But what you have purchased at the grocery store is food with titanium dioxide in it (to make your white foods whiter), and you’ve also purchased some makeup and sunblocks made with nanoparticles of titanium dioxide. And you ate your Angel Food Cake. Or you washed the makeup off your face. Or showered after a protected day in the sun. The concern is that those titanium dioxide nanoparticles could make their way through our wastewater treatment systems and ultimately end up in our rivers and streams. And cause holey fish brains.Rainbow Trout
Rainbow TroutCourtesy Timothy Knepp - U.S. Fish and Wildlife Service

In all honesty, it’s less likely that your personal usage will be directly responsible for holey fish brains and more likely that the problem rests with the large-scale manufacturing process of these products…but you’re still a key component because you’re buying what they’re selling. And so they’re making more. And now that we’ve discovered holey fish brains as a result of exposure to an ingredient in products we’re using – what should we do? Heck, holey fish brains should be concerning enough in and of itself – but let’s just take this one step further: If that’s what happens to fish, what might happen to humans?

Luckily, some important questions and conversations have arisen in the public sphere – let’s just hope the decision-makers are listening. From Nanowerk:

“The results of Professor Handy's work and that of other researchers investigating the biological effects of nanoparticles may influence policy regulations on the environmental protection and human safety of nanomaterials.

“‘It is worrying that the effects on the fish brain caused by these nanoparticles have some parallels with other substances like mercury poisoning, and one concern is that the materials may bioaccumulate and present a progressive or persistent hazard to wildlife and to humans,’ says Professor Handy.”

A writer over at Frogheart
posed some thoughtful questions, too:

  • The statement is that nanoparticles cause brain injury in fish but the researchers mention titanium di/oxide nanoparticles only. Did they test other nanoparticles as well?
  • How did they conduct the tests?
  • Did the fish ingest titanium di/oxide from the water? From their food? From both?
  • What concentrations were they exposed to?
  • Were they in an environment similar to what they’d experience naturally? Or were they in special tanks?

Good news, frogheart! Professor Handy and his team aren’t the only scientists doing this kind of research involving nanoparticles in the environment. Duke University’s Center for the Environmental Implications of NanoTechnology (CEINT) have recently shared their work on nanosilver in the environment with NISE Net, who in turn made a fascinating 6-minute video to make it all make sense:

Does Every Silver Lining Have a Cloud? from NISE Network on Vimeo.

And I happened to sit in on a panel discussion this very morning about Nanomaterials, Toxicology, and Risk, where Shannon Hanna of the University of California Santa Barbara’s Center for Nanotechnology in Society (CNS UCSB) gave a fascinating presentation about “Impacts of Zinc Oxide Nanoparticles on the Mussel.” In it, he and his team found that chronic exposure to zinc oxide had a negative impact on growth and survival on the Mediterranean Mussel.Mediterranen Mussel
Mediterranen MusselCourtesy uncredited
Nanoparticles of zinc oxide are in a whole slew of products, including the paint on boats. Boats which tend to congregate near docks. Where mussels also like to congregate. And it turns out mussels are basically Filters of the Ocean. They accumulate metals and pollutants. And then pretty much every other thing in the ocean and around the ocean (birds, us) like to eat them. Add too much zinc oxide to the mix? Runty and short-lived mussels. Hmmmm. Anyone hungry?

The studies seem to be piling up, and it’s increasingly apparent to me that nanoparticles and environment don’t play nice. Perhaps its time to start talking seriously about regulation? What do you think?

Nanotube catalyst: 10,000 X smaller than human hairs
Nanotube catalyst: 10,000 X smaller than human hairsCourtesy St Stev

Solving the carbon dioxide problem

Burning fuel releases carbon dioxide and water vapor. A breakthrough process can reverse this reaction. The carbon dioxide and water vapor can be joined into molecules of methane, ethane, or propane by using sunlight as an energy source. The secret to doing this efficiently requires a particular catalyst with a large surface area.

(A) team (at Pennsylvania State University) found it could enhance the catalytic abilities of titanium dioxide by forming it into nanotubes each around 135 nanometres wide and 40 microns long to increase surface area. Coating the nanotubes with catalytic copper and platinum particles also boosted their activity.

Learn more:
Sun-powered device converts CO2 into fuel New Scientist