Nanoparticles can harm food crops

BBC : Chemical additives in the form of tiny nanoparticles have been found to be “trickling down” into exhaust gases and some fertilizers and thus could adversely affect plant growth and fertility. Patricia Holden of the University of California, Santa Barbara, and colleagues, whose paper appears in the Proceedings of the National Academy of Sciences, looked at the effects of two common nanoparticlesâmdash;zinc oxide and cerium oxideâmdash;on soybeans, the fifth-largest global commodity crop. They found that zinc oxide, which is commonly used in cosmetics, can end up in sewage and ultimately in organic fertilizers. Although it can actually help plants grow better, it also builds up in the edible parts and can be toxic to the mammals that eat it. Cerium oxide, a common additive in diesel fuels to improve combustion and reduce particulate emissions, can get into the soil and stunt soybean growth. The study’s authors conclude that the buildup of manufactured nanomaterials in soil may necessitate greater use of synthetic fertilizers to counteract their effects.