Mercury, when dumped in lakes and rivers, accumulates in fish, and often ends up on our plates. A Swiss-American team of researchers led by Francesco Stellacci at the Ecole Polytechnique Fdrale de Lausanne (EPFL) and Bartosz Grzybowski at Northwestern University has devised a simple, inexpensive system based on nanoparticles, a kind of nano-velcro, to detect and trap this toxic pollutant as well as others. The particles are covered with tiny hairs that can grab onto toxic heavy metals such as mercury and cadmium. This technology makes it possible to easily and inexpensively test for these substances in water and, more importantly, in the fish that we eat. Their new method can measure methyl mercury, the most common form of mercury pollution, at unprecedentedly small attomolar concentrations. The system is outlined in an article appearing September 9, 2012 in the journal Nature Materials.
Methyl mercury, toxic and difficult to monitor
Researchers are particularly interested in detecting mercury. Its most common form, methyl mercury, accumulates as one goes up the food chain, reaching its highest levels in large predatory fish such as tuna and swordfish. In the US, France and Canada, public health authorities advise pregnant women to limit fish consumption because mercury can compromise nervous system development in the developing fetus.
"The problem is that current monitoring techniques are too expensive and complex," explains Constellium Chair holder at EPFL and co-author Francesco Stellacci. "We periodically test levels of mercury in drinking water, and if those results are good, we make the assumption that levels are acceptable in between those testing periods." But industrial discharge fluctuates.
A simple, inexpensive new technology
The technology developed by the Swiss-American team is simple to use. A strip of glass covered with a film of "hairy" nanoparticles is dipped into the water. When an ion
|Contact: Francesco Stellacci|
Ecole Polytechnique Fdrale de Lausanne