U.S. Autos Are Source of Mercury Pollution

KNOXVILLE — The U.S. automobile industry continues to be a major source of mercury pollution despite an industrywide push to cease using the element in car manufacturing, University of Tennessee researchers have found.

Mercury, which can have toxic effects even in small amounts, contaminates scrap metal when automobiles are shredded at recycling operations, said Gary Davis, a researcher at UT’s Center for Clean Products and Clean Technologies. The mercury is used in switches in automobile electrical systems.

“The mercury switch itself is used in automobiles to turn on the light under the hood or the light in the trunk, whenever you open the trunk or the hood. They’re also used in anti-lock braking systems,” Davis said.

The UT center, a part of the university’s Energy, Environment and Resources Center, conducted the study in collaboration with the Ecology Center in Michigan and Great Lakes United in New York, two environmental organizations.

The bulk of mercury releases occurs when contaminated steel, recovered from scrap automobiles, is melted in electric arc furnaces. Davis says the auto industry made a commitment in 1995 to end the use of mercury, but that-s not happened yet.

“There are simple and cheap alternatives that don’t use mercury,” Davis said. “The auto industry is phasing out mercury. I don’t believe it’s being phased out as fast as it could be and ought to be.

“They still have made no commitments to take care of the mercury that’s already out there in the current vehicle fleet or in cars that are already retired.”

Davis said the problem can be addressed inexpensively.

“The solution is very simple, and it’s not even that costly,” he said. “Take out the switches that are already in the cars and replace them with another switch that costs a few pennies more.

“For those vehicles that are already retired, pull the switches out before they go to the shredder.”

Davis said that there are between 175 and 200 metric tons of mercury in vehicles on the road. Toyota, Volvo and other international carmakers ended the automotive use of mercury in 1993.

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