CO₂ modifies nanoparticles

Sci. Total Environ. http://doi.org/bvjp (2016)

Up to 10,000 t of titanium dioxide nanoparticles (nTiO₂) — used in sunscreens, paints, plastics and cement, among other applications — are produced each year; a proportion of this is subsequently released into the environment. CO₂ can modify the behaviour of nanomaterials such as nTiO₂, so increasing the atmospheric CO₂ concentration may alter their environmental burden in the future when they are expected to be increasingly abundant in the environment.

Wenchao Du from Nanjing University, China, and co-authors investigate the effect of elevated atmospheric CO₂ on the toxicity of nTiO₂ to plants and soil microbes in a rice paddy experiment. They find that nTiO₂ does not affect rice plants at ambient CO₂ levels. However, under elevated CO₂ concentration nTiO₂ significantly reduces rice biomass (by 17.9%). In addition, elevated CO₂ enhances the accumulation of a number of heavy metals and reduced fat and total sugar in rice grains. These findings indicate that increasing atmospheric CO₂ may increase the toxicity of some nanoparticle contaminants, potentially reducing the nutritional quality of some crops.