Rather than dredging up the problem, or burying it under several feet of sand, they've created a patch � black geotextile mats designed to cap and stabilize pollution in place. Over the next two years, UNH associate professor Kevin Gardner, research assistant professor Jeffrey Melton, and a team of UNH students will monitor these mats to evaluate the effectiveness of this new approach.
"We need to know how these mats behave when they're buried under mud for a few years, compared to how they performed in the lab," says Melton. "What will happen to them in this intertidal zone with boats, waves, birds, and weather? How will they impact bugs and other aquatic life in the sediment?"
The mats are six feet square and one inch thick. They consist of a mixture of reactive materials sandwiched between two layers of geotextile fabric, creating a sort of quilt that traps pollutants but allows water to flow through. The reactive "filling" of this quilt contains three different substances that bind and stabilize different pollutants. One such substance � a UNH-patented technology based on a natural form of phosphorus � treats toxic heavy metals associated with industrial pollution such as lead, copper, zinc and cadmium.
"But you don't just find one pollutant at a site," says Melton. "Everything is all mixed up in the sediment." So he and his colleagues added organoclay and activated charcoal ("like in your Brita filter," he says), which adhere to and treat toxic chemicals such as polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons, (PAHs), and petroleum products that routinely enter waterways through stormwater runoff.
The project is funded by the Cooperative Institute for Coastal and Estuarine Environmental Technology (CICEET), a partnership of UNH and the National Oceanic and Atmospheric Administration, and NH Sea Grant.
"Polluted sediment is a nationwide problem," says Richard Langan, CICEET's UNH co-director. "We need better tools to identify and treat areas where this pollution has the potential to threaten human and ecosystem health. Technology demonstrations like these, that take advantage of cutting-edge science, are key to making that happen."
The mats present an alternative approach to remediating contaminated sediment; more common responses include dredging or capping sediment beneath several feet of sand. But dredging is expensive, disrupts habitats and poses the problem of how to move - and where to put - all that toxic sediment. Sand caps have questionable long-term effectiveness and can hinder boat traffic and impact aquatic life. "There's no silver bullet. What we are exploring is potentially a great tool to add to the tool box," says Melton.
Melton admits that even as Americans grow increasingly aware of environmental woes, sediment pollution does not score high on the "green glamour" scale. Yet, he points out, everyone is already feeling its impact through regular advisories that close shellfish beds or warn of eating fish contaminated by heavy metals and persistent organic pollutants like PCBs or PAHs.
"You can enjoy a great day of fishing, but if you can't eat the catch, there's a problem," says Melton. It's estimated that 20 percent of the top six inches of all sediment in U.S. rivers, lakes, streams and estuaries is contaminated. In 2004, the U.S. Environmental Protection Agency reported there were 3,221 fish consumption advisories in state waters.
Melton and Gardner chose the Cocheco not because its sediment is especially polluted, but rather because its characteristics as a well-used tidal river and its proximity to UNH make it an ideal laboratory. They plan to compare the performance of the mats in the Cocheco to those they've laid in Cottonwood Bay in Grand Prairie, Texas, adjacent to the Dallas National Air Station, in a demonstration funded by the Department of Defense's Strategic Environmental Research and Development Program (SERDP).
Moving forward, researchers from the Contaminated Sediments Center, part of UNH's Environmental Research Group, plan to test new sampling technologies that measure the scope and potential threat of contamination in sediment. In addition, they're always on the lookout for new test sites.
To learn more about UNH's Contaminated Sediments Center, go to http://www.unh.edu/erg/ccsr/index.html.
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27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
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21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
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