Dentists eyed in mercury reduction efforts

By Brent Killackey

Wednesday, July 11, 2007 2:12 AM CDT

Journal Times

RACINE -

As the Department of Natural Resources pressures the city of Racine to reduce mercury discharged into Lake Michigan as part of the city's treated wastewater, the city is turning its focus on dentists.

The City Council is considering an ordinance that will require dentists to install what's called an amalgam separator, a device that screens out mercury in wastewater from tooth fillings.

"The highest contributor to the actual mercury in the wastewater and one of the easiest to remove is the dentist," said Nora Erlandson, lab director for the city's wastewater utility.

The DNR requires municipalities to create a mercury pollution minimization plan if their treated wastewater exceeds a mercury level of 1.3 nanograms per liter. In 2007, Racine's

treated wastewater averaged 3.8 nanograms per liter, Erlandson said.

These are small amounts - nanograms measure a billionth of a gram. "Unfortunately, it doesn't take much mercury to contaminate a lake," Erlandson said.

All dentists east of Interstate 94 would be affected by the city's ordinance because all of the communities use Racine's wastewater treatment system, according to Keith Haas, general manager of Racine's water and wastewater utilities.

The Racine City Council's Public Safety and Licensing Committee backed the proposed ordinance on Monday. The full council is expected to vote on ordinance July 17.

Nearly all of Racine's dentists follow the best management practices for amalgam and many already have separators, Erlandson said.

Anticipating coming mercury-reduction requirements in the state, the Spring Dental Group, 5540 Spring St., installed a separator around two to three years ago, according to Ned Murphy, a dentist at the clinc. The separator, which removes 99.9 percent of mercury from the wastewater, cost just under $3,000 for the three-dentist clinic.

Mercury is one component of the common metallic fillings, and nearly all dentists consider the compound's use in fillings safe, Murphy said.

"There's been no demonstration of any harm that's come to patients from the amalgam fillings," Murphy said. "The mercury is bound in the fillings."

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