- A recent experiment has shown that titanium dioxide nanoparticles, used for killing harmful and unpleasant bacteria in applications such as wastewater treatment and delivering cancer treatment drugs, may also kill ocean phytoplankton when the particles, suspended in seawater are excited by ultraviolet light.
- Phytoplankton are very small marine organisms (most are too small to be seen with the unaided eye) that regulate the global climate by taking up vast quantities of carbon dioxide, or CO2, from the atmosphere via photosynthesis. They also serve as the first link in the oceans’ food chain.
- Titanium dioxide is the most commonly used nanoparticle, and likely to enter water bodies from industrial discharge. Nanoparticles are highly reactive with oxygen after exposure to ultraviolet (UV) light. Meanwhile, nanoparticles suspended in water can easily attach to phytoplankton cell membranes. Damage to plankton occurs when titanium dioxide is electronically excited due to energy from UV light.
The effect is well established for artificially high levels of UV light, however this new research suggests that normal levels of UV from sunshine can cause the same effect and may highlight the need for precautionary measures to prevent the increase in nanoparticles entering marine ecosystems.
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