Volume 12, Number 2, 2003
Now that leaded gasoline is a thing of the past in the United States, stepping on the accelerator no longer sends toxic metals into the environment.
Stepping on the brakes is another matter.
"There are two automotive sources that remain for metals in the environment, copper from brake pads and zinc from tires," says Herbert Allen, professor of civil and environmental engineering and director of the Center for the Study of Metals in the Environment. The center, a consortium of eight educational institutions, is headquartered in UD's College of Engineering.
"Copper gets scraped off the pads every time you apply the brakes in a car," Allen says. "That's the sticky black gunk you see on your hubcaps. Tires contain zinc, which gets into the environment as the tires wear down, especially when you leave skid marks on a road surface. In both these cases, the questions that need more study are: How much metal from these sources actually gets into our waterways? And, is the amount significant?"
A research project getting under way at the College, under the auspices of the metals center, will explore those issues. The environmental effect of brake pads has become a hot topic recently, with elevated levels of copper found in the southern portion of San Francisco Bay, which has failed state water-quality standards. Some research has implicated brake pads as a significant source of this copper, and Allen says more investigation of the situation is needed for that bay and for other bodies of water.
The automotive research is just one example of numerous studies being conducted as the Center for the Study of Metals in the Environment begins its second year of full operation. Other projects include research on metals that wash downstream from mining operations, metals in urban-influenced watersheds such as the Chesapeake and the ways metals bind to soil.
At the University, the center's research is being carried out not only in the College of Engineering but also in the colleges of Marine Studies and Agriculture and Natural Resources.
The center was established two years ago and was fully operational, with research funded by the federal Environmental Protection Agency, during the 2002-03 school year. In addition to UD, the consortium includes the Colorado School of Mines; Manhattan College; McMaster, Ohio State and Oklahoma State universities; and the universities of Wyoming and Missouri at Rolla.
The center's research focuses on nonferrous metals that have had economic and environmental importance--in particular, copper, cadmium, lead, nickel and zinc--and their effects on water and soil. Although these metals have been widely studied, Allen says, regulators who set standards for water quality still lack important scientific information that would allow them to predict the metals' impact.
The center's researchers do field work and mathematical modeling, with the eventual goal of setting up a model that will be able to predict the effects of metals.
"What we're doing is making better tools for assessment, which we hope state and federal regulators will avail themselves of," Allen says. "We want to give them a knife with a sharp edge, a much more precise tool than they have now."
A key researcher working toward that goal is Dominic Di Toro, who joined the UD faculty in January as Distinguished Professor of Civil and Environmental Engineering. Regarded as a pioneer in the field of water quality modeling, he is the author of the book Sediment Flux Modeling and more than 60 technical papers, and
he has participated in numerous water quality studies for industry and governmental agencies.
Di Toro is working with a "Unit World" model--a hypothetical environment that will allow scientists and regulators to predict how different metals affect water systems and evaluate the associated environmental hazard posed by each.
"If you put copper in a lake, for example, you want to answer the question of where it goes. Does it stay dissolved? Does it form minerals? Does it settle in the sediment?" Di Toro says. "You start with the principle of mass balance: Everything has to go somewhere. Then, you develop mathematical models from there." Once researchers can predict where various metals end up, he says, they can begin to determine their effect on living things.
Similar models have been used for some time to predict and evaluate the effects of organic compounds, such as the pesticide DDT, "but it turns out that metals are more complex," Di Toro says.
The center's research projects are being conducted at various member institutions, but Allen says there's a high level of collaboration, with all the projects contributing to the same end result.
"Our view of a center is that you don't just do a bunch of projects," he says. "Instead, those projects come back together to be integrated into an overview."
--Ann Manser, AS '73, CHEP '73