Iron nanoparticles that are poised for use in large-scale pollution remediation can rapidly react with oxygen and cause lung cells to die.

The number of oxygen molecules associated with iron nanoparticles is an important factor in its toxicity to cells, finds a study published in the journal Environmental Science and Technology. Iron-based nanoparticles without attached oxygen molecules can react quickly when exposed to oxygen to form other reactive varieties that can damage lung cells.

It is important to understand which types of nanoparticles may be most harmful to cells. Of most concern are the health and safety of the workers who could be highly exposed when they make the materials.

Nanoparticles are very small materials usually made from carbon or metals. They are increasingly used in far-ranging applications such as consumer products, medical therapies and industrial processes. Because of their small sizes, nanoparticles react differently with their surroundings than the bulk materials they are made from.

One type – called zero-valent iron nanoparticles (nZVI) – has great potential for remediating pollutants such as chlorinated organic solvents, pesticides and metals found in contaminated groundwater. nZVI is already commercially available, and its use could introduce large amounts of the nanoparticles into the environment.

However, the same qualities that make these particles potentially useful in environmental clean-up – namely their high reactivity – also make them potentially harmful to living things. Some of the reactions can release free radicals that can damage cell DNA in a process broadly called oxidative stress. Prior studies have found that particulates can cause toxicity to lung cells via oxidative processes.