August 2007, Vol. 19, No.8
Researchers Examine Silver Nanoparticles in Wastewater Systems
It’s a nano world. Many everyday consumer items now utilize the emerging science of nanotechnology, so researchers at
August 2007, Vol. 19, No.8
Researchers Examine Silver Nanoparticles in Wastewater Systems
It’s a nano world. Many everyday consumer items now utilize the emerging science of nanotechnology, so researchers at the University of Missouri–Columbia will examine whether the technology poses future problems for the environment, according to a university news release. The study focuses on silver nanoparticles usage in wastewater treatment plants.
“Silver nanoparticles are emerging as one of the fastest growing nanomaterials with wide applications,” said Zhiqiang Hu, assistant professor of civil and environmental engineering in the College of Engineering. “Currently, little is known about the adverse effects of silver nanoparticles to human health and their fate in ecological systems.”
Hu will be working with Baolin Deng, an associate professor of civil and environmental engineering in the college, to study silver nanoparticles — specifically, their potential affects on wastewater treatment systems, the news release notes. They have received an $84,000 grant from the National Science Foundation (Arlington, Va.). The study began in June and will take about 1 year to complete, according to the news release. Hu and Deng will determine how silver nanoparticles interact with bacteria that are used for wastewater treatment.
“Nitrifying bacteria is extremely sensitive to metal toxins and could serve as a potential environmental health indicator,” Hu said. “Over time, a small volume of nanoparticles will accumulate in our sewage plants.”
The engineers want to find out if silver nanoparticles, known for their bacteria-fighting ability, effectively defend against bacteria found in treatment plants. Hu said the particles enter sewage systems following the washing of hands after people have handled the “nanotechnology enhanced” products. Some of those products include bandages, clothing, cosmetics, car wax, and toys.
Hu said laundry detergents, soaps, water filters, and washing machines also employ nanotechnology and can directly dispense silver nanoparticles into the sewage system.
Contact Hu at email@example.com.
Ski Area Affects Mountain Watershed, Study Shows
In recent decades, mountain regions in many parts of the world have faced growing development pressures from recreation and tourism uses, such as vacation homes and ski areas. Despite these new uses, most scientific studies of soil and water in high-elevation areas have focused on the effects of traditional resource extraction, such as logging, according to a University of Vermont (UV; Burlington) news release. The impact of ski-resort developments on watersheds is little understood.
In the first study to document the effects of existing ski-resort development on water flows and water quality in the northeastern United States, Beverley Wemple, associate professor of geography at UV, and her colleagues have studied two side-by-side mountain watersheds on the eastern slopes of Mount Mansfield in Vermont. The nearly pristine Ranch Brook watershed served as a control, while the adjacent West Branch watershed contains the Stowe Mountain Resort.
Their results — published April 24 in the journal Hydrological Processes — show surprising differences between the two watersheds, according to Wemple. The differences, the news release notes, include greater water volume, chloride (likely from parking-lot salt runoff), and sediment (likely from land clearing) flowing out of the developed watershed.
“Our results suggest the hydrologic effects of resort development may be more pronounced than the effects of timber extraction,” Wemple said.
The data presented in Hydrological Processes “will give us a baseline for evaluating the impacts of the new resort expansion that has taken place at Stowe [Vt.] in recent years,” Wemple said, and is part of a long-term study there that “will provide scientific grounding for other proposed resort expansions in the region.”
The study analyzes data collected from 2001 to 2003. Next, the researchers are moving on to analyze the data they have been collecting during a major expansion of the ski area that began in 2004.
“We’re concerned that folks are going to interpret these results to say, ‘this is all the ski area’ or ‘the ski area is a problem,’” said James Shanley, one of Wemple’s co-authors, who works for the U.S. Geological Survey in Montpelier, Vt. “But we can’t — and don’t — say that. We’re just laying out what we’re seeing.” For example, he points out that a considerable portion of the water volume differences may be caused by natural variation between the two watersheds, the press release states.
“The ski areas may be pleased by these results because there are no glaring water quality impacts that we show are connected to the existence of the ski area,” Shanley said.
Nevertheless, Wemple said, “there is a lot more water coming off this developed watershed than we would have thought originally,” and a “measurable” amount of change in the water flowing through the West Branch watershed can be attributed to the ski area. In the developed watershed, water yields were 18% to 36% higher than the control, chloride about 20 times higher than a natural forest basin, and suspended sediment more than 2.5 times greater.
“The way we deal with that, when we do development, is to plan for more stormwater than we have traditionally or than existing studies suggest we should,” Wemple said. “If we know what we