A study undertaken by the University of Missouri and the U.S. Geological Survey has apparently found that carbon nanotubes could affect invertebrate aquatic species. Joseph Mwangi, et al., “Toxicity of carbon nanotubes to freshwater aquatic invertebrates,” Environmental Toxicology & Chemistry, August 2012. The study exposed amphipoda (Hyalella azteca), midgea (Chironomus dilutus), oligochaeta (Lumbriculus variegatus), and mussels (Villosa iris) to water containing one gram per liter of carbon nanotubes from different sources.

The researchers found reduced survival and growth for these invertebrates when exposed to the carbon nanotubes, but the effect varied depending on the type and source of the carbon nanotubes. The effects also depended on (i) whether the materials were precleaned by acid to remove soluble metals, (ii) whether sonication was used to disperse the materials, and (iii) which organism species was tested. The authors concluded, “The results suggest that releases of as-produced carbon nanotubes will cause toxic effects on the benthic invertebrates. This will not only reduce the population of the invertebrates, but also likely interfere with ecological balances and has the potential to disrupt the food chain in the impacted area.”