There is a related issue concerning mercury in the environment. It's clear that mercury is toxic to humans. It is also well established that mercury is a significant environmental contaminant, and there are millions of dollars spent on cleaning up toxic sites from industrial sites that have spilled mercury. There is also a great deal of effort being made to control mercury emissions from industrial settings where mercury is used. Here in Washington State, the Department of Ecology has included mercury on its list of the top nine targeted "Persistent Bio-accumulative Toxins" (PBT's) to be eliminated in our environment. What has been overlooked, until fairly recently, is that dentistry is one industry that is spilling a significant amount of mercury into the environment!
Wastewater treatment agencies in several parts of the U.S. and Canada recently have been studying this problem in earnest. They find that wastewater entering the municipal treatment plants, often contains unacceptable levels of heavy metals, including mercury. Wastewater treatment plants are not designed to process heavy metals. It is important that this contamination is cut off at the source. Their studies have estimated that anywhere from 14% to 70-80% or more of the mercury contamination of wastewater entering the treatment plants is coming from dental offices!
How does this happen? Any time a mercury amalgam filling is placed or removed, there is a significant amount of amalgam sludge that is vacuumed up by the chairside dental assistant. It doesn't just disappear. That mercury-laden sludge goes down the drain and into the wastewater system. In most offices, this goes completely unchecked. Several European countries have had regulations for years that require dental offices to be equipped with special mercury-separator devices that filter out or trap mercury before the wastewater leaves the dental office. As of January, 2001, no such regulations exist in any U.S. area. This year, such regulations will begin to take effect in some Canadian cities, and it is likely that parts of the U.S. will follow shortly. There is also mercury vapor contained in air vented to the outside of dental office buildings and as yet no easy technological solution for this emission.
We are proud to say that we have had such a wastewater protective service in place for several years. In fact, we were on of the very first installed in the U.S. We continue to fight to make this a required feature of all dental offices. It's a simple step that makes a significant environmental impact.