Metro Sewage Authorities Contradict ADA on Waste Mercury Amalgam in Wastewater

It is unfortunate that organizations who critique the American Dental Association’s (ADA) assumptions and junk science hardly ever get interviewed or covered by the press. The ADA usually gets a free pass to promote what ever nonsense they like without being called out on it. Case in point. In October, 2002, the ADA released a Scientific Assessment entitled “Evaluation of Mercury in Dental Facility Wastewater.” The report argued that dental offices were not a significant source of mercury contamination, and that existing practices were sufficient to keep mercury emissions low. The Association of Municipal Sewage Authorities released a critique of the ADA report in December, 2002, taking serious issue with most of its findings.

While it is long and detailed, but here are a few criticisms:

General Comments

1. The report incorrectly implies that publicly owned treatment works (POTWs) are designed to handle dental mercury. The report must be revised to reflect that this not the case.

2. The report incorrectly implies that publicly owned treatment works (POTWs) are designed to handle dental mercury. The report must be revised to reflect that this not the case.

3. The report makes definitive statements and assumptions about the bioavailability of mercury in dental amalgam with little or no supporting evidence. 

4. the report does not consider air emissions during placement and removal of amalgams (0.7tons/year for 1994-95, per the U.S. EPA, 19973), nor does it consider mercury from amalgam that contaminates human waste from teeth grinding, or mercury air emissions from cremation of human remains with amalgam fillings.

5. ADA should acknowledge that their model of the national impact of dental discharges is based on little to no real data. ADA’s contractor, ENVIRON International Corporation, uses assumptions and extrapolation, even when real data could be used. 

Specific Comments

Executive Summary:

The ADA concludes that the dental community releases small amounts of mercury when compared to various facilities that may release mercury. While the ADA maintains that the total quantity of mercury released to all environmental media is minimal, analysis by the City of Wichita (Wichita, Kansas) has found that the dental community is the largest source contributor of mercury to the POTW. These findings are consistent with studies conducted by AMSA and other AMSA members. POTWs are not designed to carry, treat and remove mercury, and are required to meet stringent effluent discharge criteria as well as biosolids land application criteria.

AMSA Critique ADA Assessment 2