Dental chair a possible source of neurotoxic mer...(the answer Rockne said. Based on th...)

Based on their sample studies, the researchers estimate that 2-5 kilograms, or up to 11 pounds, of methyl mercury could be entering the public water supply of the United States each year from dental waste water. While this may not seem like much, methyl mercury is highly toxic in minute amounts.

When in waterways, methyl mercury tends to get biomagnified up the food chain, moving from algae and phytoplankton to fish and, ultimately, to humans.

While surprised by the level of contaminants found in the study, Rockne says follow-up research is necessary -- then, possibly, some basic engineering.

"Amalgam separators are a good first step, but maybe something else is necessary downstream to prevent further methylation and prevent further soluble mercury from getting through the system," he said.

"We have to take more steps to prevent the problem from occurring in the first place," he said. "We're dealing with a pipe -- a control point. As an engineer, I see this as a problem that is tractable -- something we can definitely do something about."

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