Studying environmental impacts of nanoparticles using mesocosms

Mesocosms. Credit: Benjamin Coleman

The advent of new technologies is typically followed by new government regulation, and in the absence of data, fear-based reactionism can have far too much influence on policy. Quality research studies on real risks and impacts of nanoscale technologies can help lead to legitimate scientific consensus and appropriate regulation.

Engineered nanoparticles draw particular attention, because the same unique properties that give rise to special utility may also give rise to special health and environmental risks.

To calibrate our responses to nanoparticle toxicology studies, it is important to note whether an experiment reasonably represents likely exposure scenarios and whether nanoscale size is in fact a contributing factor to observed effects.

Recently highlighted at, researchers at Duke University are investigating environmental impacts of widely used silver nanoparticles by way of experiments that seek to represent real-world exposure levels.

Previous studies have involved high concentrations of the nanoparticles in a laboratory setting, which the researchers point out, doesn’t represent “real-world” conditions.

For their studies, the researchers created mesocosms, which are small, man-made structures containing different plants and microorganisms meant to represent the environment. They applied sludge with low doses of silver nanoparticles in some of the mesocosms, then compared plants and microorganisms from treated and untreated mesocosms after 50 days.

“We’re trying to come up with the data that can be used to help regulators determine the risks to the environment from silver nanoparticle exposures,” [said Benjamin Colman, a post-doctoral fellow in Duke’s biology department and a member of the Center for the Environmental Implications of Nanotechnology (CEINT)].

“Our results show that silver nanoparticles in the biosolids, added at concentrations that would be expected, caused ecosystem-level impacts,” Colman said.

The researchers plan to continue to study longer-term effects of silver nanoparticles and to examine another ubiquitous nanoparticle – titanium dioxide.

Studies that do not elucidate the roles of different particle properties can still be of great benefit by drawing attention to studies that do, and by adding to the pool of reliable data. Most important is for researchers and the public alike to recognize the difference and to support policy that is sensible and appropriate.
-Posted by Stephanie C

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