| | A study finds that metal nanoparticles may have deleterious effects on plant growth and soil fertility. Nanoparticles are increasingly used in consumer products and accumulate in soils in part via land application of biosolids, the nutrient-rich residue from wastewater treatment. John Priester and colleagues investigated whether the presence of two commonplace nanoparticles—zinc oxide and cerium oxide—in soils adversely affects soybean plants or the plants' symbiotic nitrogen-fixing microbes that fertilize the soil. The authors cultivated soybean plants in greenhouses, with varying amounts of either metal oxide nanomaterial added to the soil, and monitored the plants' growth over time. Although the zinc particles slightly stimulated the growth of the plants, the authors discovered that zinc accumulated throughout the edible parts of the plants, including the leaves and beans. By contrast, the cerium particles stunted plant growth and reduced soybean yields. Furthermore, the authors found that the cerium particles entered the plants' roots and almost completely inhibited nitrogen fixation carried out by the microbes that dwell in the plants' root nodules. The findings suggest that the buildup of manufactured nanomaterials in soils may compromise soil-based crop quality and yield, and may necessitate greater use of synthetic fertilizers, according to the authors. "Soybean susceptibility to manufactured nanomaterials with evidence for food quality and soil fertility interruption," by John H. Priester, et al.
10.1073/pnas.1205431109 [Abstract]
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