Hospitals, Dentists Could Reduce Mercury Pollution, Study Finds

April 9, 1998

GAINESVILLE — Although a majority follow the rules, some Florida hospitals could do more to remove mercury from medical waste or to replace mercury-containing devices such as traditional thermometers, a University of Florida study has found.

The yearlong study by UF’s Florida Center for Solid and Hazardous Waste Management also found dentists don’t consistently dispose of mercury properly. Some allow mercury-containing material from old fillings to escape into sewer pipes that drain into wastewater treatment plants, for example.

The Florida Department of Environmental Protection commissioned the roughly $50,000 study as part of efforts to reduce pollution by the toxic metal statewide. Medical waste incinerators, solid waste incinerators and power generating plants are the three biggest sources of airborne mercury emissions in the state, DEP officials said.

“We have an agency goal to reduce the amount of mercury, cadmium and lead in solid waste by 50 percent by the year 2000,” said DEP Environmental Specialist Jack Price. “This study plugs into an area where we have some opportunities.”

Mercury is a neurotoxin to humans and other animals. It can cause blindness, deafness and death and is particularly harmful to children’s developing nervous systems.

Released into the environment from incinerators or fossil fuel power plants in a vaporized form, the metal is absorbed by small organisms, then changed into a more toxic, organic form that moves up the food chain. The result is “bioaccumulation” — the amount of mercury increases with each step, so humans and other carnivores get the biggest doses.

Mercury poisoning is likely a factor in the deaths of two Florida panthers in the late 1980s and could be causing behavioral changes in Florida’s bald eagle population.

Meanwhile, government advisories urging fishermen to limit their fish intake due to mercury contamination are becoming a familiar sight. Currently, 89 Florida waters are posted with such advisories, with some warning people to avoid eating any fish.

Under state and federal regulations, mercury-containing devices and most mercury-containing lamps are classified as hazardous wastes, and it is usually against the law to knowingly dispose of these wastes in incinerators or landfills.

But the study, which included a detailed survey of 92 of the state’s hospitals, found workers at some hospitals didn’t always separate mercury wastes properly, unintentionally disposing of mercury waste in medical waste bound for incinerators. Thermometers, for example, should be placed in hazardous waste containers. But broken thermometers are sharp, and some workers reported disposing of them in so called “sharps” containers used for waste hypodermic needles. Some hospitals, meanwhile, reported throwing away materials used to clean up mercury spills in infectious waste “red bags.”

“The results suggest that while the majority of hospitals in Florida are following the rules and recommended practices with regard to mercury spills and mercury-containing devices, compliance is far from unanimous,” the study said.

The chief source of mercury pollution from dental offices was in the disposal of a material known as amalgam used for old fillings, the study found.

When old amalgam is drilled out of a patient’s tooth, it is sucked into a vacuum device and released to sewer pipes. Though drain traps help reduce the amount of amalgam entering the sewer, they don’t catch all of it, the study found. Dentists visited as part of the study estimated as much as half of amalgam was reaching the sewer.

Education is needed to help dentists’ offices and hospitals change disposal practices, and to encourage hospitals to recycle mercury-containing items and replace them with alternatives, said John Schert, director of the College of Engineering-based Center for Solid and Hazardous Waste Management.

“We need to look at how we can help hospitals on this issue in terms of what alternatives are out there for them,” he said.

As a result, the center has hired a full-time staffer to work with hospitals and dentists on mercury-related issues, Schert said. DEP officials will use information collected as part of the program to establish recommended management practices, Price said.

“Hospitals visited as part of the survey were eager to learn about proper mercury handling procedures, and we expect these management practices to help guide them in their efforts to reduce this pollution problem,” Price said.