Tuesday, August 21, 2012

Nanosized pollutants pose crop risks

Janet Raloff in Science News:  Nanoscale pollutants can enter crop roots, triggering a host of changes to plants’ growth and health, two studies find. These tiny particles can stunt plant growth, boost the plants’ absorption of pollutants, and increase the need for crop fertilizers.

Nanomaterials that get released in the exhaust from diesel-fueled tractors can rain down onto crop fields. Those used in fabrics, sunscreens and other products collect in the solids separated out of sewage and wastewater — nutrient-rich solids that are routinely spread on U.S. fields to improve soils. The new studies offer a glimpse at the toxic effects such nanoparticles may pose to future crops as exposures rise.

The new data now “forewarn of agriculturally associated human and environmental risks from the accelerating use of manufactured nanomaterials,” Patricia Holden of the University of California, Santa Barbara, and her colleagues report in one of the studies, published online August 20 in the Proceedings of the National Academy of Sciences.

Manufacturers have been turning to nanoparticles in recent years because they perform differently than larger-scale versions of the same product, notes Jason White of the Connecticut Agricultural Experiment Station in New Haven. If nanoscale materials behave differently, both chemically and physically, he asks, “Why should we have assumed they’d behave the same biologically?”...

Two microfabricated grippers touching each other inside a nanomanipulation setup in an electron microscope, shot by Kristian Molhave, Wikimedia Commons, under the Creative Commons Attribution 2.5 Generic license

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