Health officials warn pregnant women and children to avoid eating certain kinds of fish. Mercury built up in the fish can damage the nervous system and impair children’s mental development. The National Academy of Sciences says at least 60,000 American children are born at risk for impaired development every year because their mothers were exposed to mercury. Mercury has been eliminated from paint, batteries, and other products. Now, some dentists are doing their part to reduce the mercury going into the environment. The Great Lakes Radio Consortium’s Stephanie Hemphill reports:
Health officials warn pregnant women and children to avoid eating certain kinds of fish.
Mercury built up in the fish can damage the nervous system and impair children’s mental
development. The National Academy of Sciences says at least 60,000 American children
are born at risk for impaired development every year because their mothers were exposed
to mercury. Mercury has been eliminated from paint, batteries, and other products. Now,
some dentists are doing their part to reduce the mercury going into the environment. The
Great Lakes Radio Consortium’s Stephanie Hemphill reports:
Mercury is an essential part of dental amalgam, the silver stuff used to fill cavities. The
mercury keeps the amalgam soft until it’s pressed into the cavity, then it bonds to form a
very stable, durable filling. The problem is the small bits of amalgam that are left over
after the cavity is filled. The suction hose that cleans them out of your mouth generally
dumps them down the drain. So they can easily end up in a lake or river, where they can
be eaten by fish.
The average dental office creates about a half pound of waste mercury every year. Just a
tiny portion of that would be enough to warrant fish advisories.
“The amount that’s sewered from dental offices is probably the largest input to the sewer
Tim Tuominen is a pollution prevention specialist with the Western Lake Superior
Sanitary District in Duluth. He’s been working with dentists in the city for nearly ten
years to reduce the mercury they wash down the drain.
He started with the vacuum systems nearly all dentists already have. When the suction
hose whisks amalgam out of your mouth, the pieces are held in a container to keep them
from damaging the vacuum pump. Tuominen showed the dentists how to empty the
container and bring the contents to the district’s recycling program.
In the first two years, the amount of mercury coming into Duluth’s wastewater treatment
plant was cut in half, and it’s been reduced even further since then.
To cut down on mercury even more, Tuominen got a grant to buy more expensive
equipment that captures up to 99% of the amalgam. He offered the equipment free to any
dentist who would agree to use it.
“I’ll go in and install them, train the assistants and the dentists how they operate, that only
takes about half an hour, then after six months I show them how to manage the solids
particles that collect in them over that time period. So it’s really pretty simple.”
Most of the dental offices in Duluth have installed the systems, and Tuominen expects the
rest to follow suit.
Lorraine Kellerman operates the system in one dental office. Once a week she empties
the chair-side traps and puts the chunks of amalgam into a container for recycling. Then
she goes down to the basement where a tank, like an aquarium, collects the finer particles.
The heavy amalgam settles to the bottom of the tank.
“We just put the hose in the drain, turn the lever, and you just wait ’til the fluid runs out
and then you can come back down, it doesn’t take long, it only takes a few minutes
Once a year the amalgam that collects at the bottom is cleaned out and recycled.
Kellerman’s boss is dentist Jim Westman.
“The beauty of this technology is in its simplicity. Gravity works, it’s simple, it’s very
Westman says the dentists in Duluth are happy to use the equipment. It costs about
$500, and the recycling charge is about $50 a year.
Westman is chair of the Minnesota Dental Association’s environmental committee. It’s
been working on a plan to help dentists around the state of Minnesota reduce their output
of mercury. Westman says they want to make it easy for dentists.
“No matter where someone has question in regards to what’s going to work in my
equipment, there’s so many variations from one office to the next, who are my resources
to call or handling, transport, process materials, it’s that who you going to call side of the
question that’s going to make a difference as we build a bigger program. ”
If the voluntary program catches on in Minnesota, it could spread to other states. Michael
Bender is director of the Mercury Policy Project, a national organization working to
reduce mercury in the environment. He says dentists around the country are beginning to
feel they should do their part.
“It’s part of the cost of doing business. It’s not going to break any dentist’s back
financially to cover the cost of doing whatever it takes to be a good business, responsible
to the community, responsible to the environment.”
In December, the Environmental Protection Agency is convening a meeting on dental
mercury. The agency will publish information on ways state and local governments can
keep dental mercury out of the environment.
For the Great Lakes Radio Consortium, I’m Stephanie Hemphill.