The Bren School-based authors of a study published Jan. 20 in the journal PLoS ONE have observed toxicity to marine organisms resulting from exposure to a nanoparticle that had not previously been shown to be toxic under similar conditions.
Lead author and assistant research biologist Robert Miller and co-authors Arturo Keller and Hunter Lenihan – both Bren School professors and lead scientists at the UC Center for Environmental Implications of Nanotechnology (UC CEIN) – Bren Phd student Samuel Bennett, and Scott Pease, a former UCSB undergraduate and current graduate student in public health at the University of Washington, found that the nanoparticulate form of titanium dioxide (TiO2) exposed to ultraviolet radiation (UVR) can be toxic to marine organisms.
"Application of nanomaterials in consumer products and manufacturing is quickly increasing, but there is concern that these materials, including nanoparticles, may harm the environment," says Miller. "The oceans could be most at risk, since wastewater and factory discharges ultimately end up there."
Nano-titanium dioxide is highly reactive to sunlight and other forms of ultraviolet radiation (UVR,) the authors write, adding that TiO2's property of generating reactive oxygen species (ROS) when exposed to UVR makes it useful in antibacterial coatings and wastewater disinfection, and potentially valuable as an anti-cancer agent.
Until now, they say, no research has demonstrated that photoactivity causes environmental toxicity of TiO2 under natural levels of UVR.
"Previous experiments have suggested that TiO2 does not affect aquatic organisms, but these experiments used artificial lighting that generated much lower levels of UVR than sunlight," Miller explains. "In these new experiments, we used lights simulating natural sunlight."
But now, the authors say, "We show that relatively low levels of ultraviolet light, consistent with those found in nature, can induce toxicity of TiO2 nanoparticles to marine phytoplankton, the most important primary producers on Earth.
"With no exposure to UVR, the TiO2 had no effect on phytoplankton, but under low-intensity UVR, ROS in seawater increased with increasing concentrations of nano- TiO2."
The concern is that rising concentrations of nano- TiO2 "may lead to increased overall oxidative stress in seawater contaminated by TiO22, and cause decreased resiliency of marine ecosystems."
The authors suggest, therefore, that UVR exposure should be considered when conducting experiments to determine the ecotoxicity of nanomaterials having photoactive potential.
James Badham | EurekAlert!
New application for acoustics helps estimate marine life populations
16.01.2018 | University of California - San Diego
Unexpected environmental source of methane discovered
16.01.2018 | University of Washington Health Sciences/UW Medicine
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
16.01.2018 | Materials Sciences
16.01.2018 | Materials Sciences
16.01.2018 | Power and Electrical Engineering