Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mercury in Water, Fish Detected with Nanotechnology

13.09.2012
Inexpensive, super-sensitive device detects even low levels of toxic metals in water, fish
When mercury is dumped into rivers and lakes, the toxic heavy metal can end up in the fish we eat and the water we drink. To help protect consumers from the diseases and conditions associated with mercury, researchers at Northwestern University in collaboration with colleagues at Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, have developed a nanoparticle system that is sensitive enough to detect even the smallest levels of heavy metals in our water and fish.

The research was published September 9 in the journal Nature Materials.

“The system currently being used to test for mercury and its very toxic derivative, methyl mercury, is a time-intensive process that costs millions of dollars and can only detect quantities at already toxic levels,” said Bartosz Grzybowski, lead author of the study. “Ours can detect very small amounts, over million times smaller than the state-of-the-art current methods. This is important because if you drink polluted water with low levels of mercury every day, it could add up and possibly lead to diseases later on. With this system consumers would one day have the ability to test their home tap water for toxic metals.”

Grzybowski is the Kenneth Burgess Professor of Physical Chemistry and Chemical Systems Engineering in the Weinberg College of Arts and Sciences and the McCormick School of Engineering and Applied Science.

The new system is comprised of a commercial strip of glass covered with a film of “hairy” nanoparticles, a kind of a “nano-velcro,” that can be dipped into water. When a metal cation --- a positively charged entity, such as a methyl mercury --- gets in between two hairs, the hairs close up, trapping the pollutant and rendering the film electrically conductive.

A voltage-measuring device reveals the result; the more ions there are trapped in the “nano-velcro,” the more electricity it will conduct. To calculate the number of trapped particles, all one needs to do is measure the voltage across the nanostructure film. By varying the length of the nano-hairs covering the individual particles in the film, the scientists can target a particular kind of pollutant that is captured selectively. With longer “hairs,” the films trap methyl mercury, shorter ones are selective to cadmium. Other metals also can be selected with appropriate molecular modifications.

The nanoparticle films cost somewhere between $1 to $10 to make, and the device to measure the currents costs a few hundred dollars, Grzybowski said. The analysis can be done in the field so the results are immediately available.

Researchers were particularly interested in detecting mercury because 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 United States, France and Canada, public health authorities advise pregnant women to limit fish consumption because mercury can compromise nervous system development in the fetus.

Researchers used this system to detect levels of mercury in water from Lake Michigan, near Chicago, among other samples. Despite the high level of industry in the region, the mercury levels were extremely low.

“The goal was to compare our measurements to FDA measurements done using conventional methods,” said Francesco Stellacci of EPFL, co-corresponding author of the study. “Our results fell within an acceptable range.”

The researchers also tested a mosquito fish from the Florida Everglades, which is not high on the food chain and thus does not accumulate high levels of mercury in its tissues. The U.S. Geological Survey reported near-identical results after analyzing the same sample.

"This technology provides an inexpensive and practical alternative to the existing cumbersome techniques that are being utilized today,” said Jiwon Kim, graduate student in Grzybowski’s lab in the department of chemistry at Northwestern. “I went to Lake Michigan with our sensor and a hand-held electrometer and took measurements on-site in less than a minute. This direct measurement technique is a dream come true for monitoring toxic substances."

This work was supported by the Non-equilibrium Energy Research Center, which is an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under grant number DE-SC0000989.

Authors of this study include: Jiwon Kim, Baudilio Tejerina, Thomas M. Hermans, Hideyuki Nakanishi, Alexander Z. Patashinski and Bartosz A. Grzybowski from the Department of Chemical and Biological Engineering and Department of Chemistry, Northwestern University; Eun Seon Cho and Francesco Stellacci, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne EPFL Switzerland and Hao Jiang and Sharon C. Glotzer, Department of Chemical Engineering and Department of Materials Science and Engineering, University of Michigan.

Erin White is the broadcast editor. Contact her at ewhite@northwestern.edu

Erin White | EurekAlert!
Further information:
http://www.northwestern.edu

More articles from Ecology, The Environment and Conservation:

nachricht Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>