Oral Health Group

HEALTH ISSUES: Environmental Issues Concerning Mercury Emissions from Amalgam Waste and the Responsibility of Dental Clinics in Canada

June 1, 2001
by Yves Hennekens, Economist and Environmentalist, MSc., Public Adm

Very shortly, many major cities in Canada will impose the use of amalgam separators in dental clinics. This obligation will be linked to others concerning the appropriate management of amalgam waste collected by dental clinics. During the Summer of 2000, the City of Toronto and the Montreal Urban Community (MUC) adopted new by-laws concerning wastewater in the sewage systems and specific legislative measures for dental clinics. Last Fall, the Capital Regional District (CRD) in British Columbia took a similar step, imposing as early as July 1st 2001, the use of amalgam separators for dental clinics in its territory.

It’s not a coincidence. The Canadian process should precede a wider movement in North America. It is quite legitimate to ask: “Why are Canadian and US authorities now targeting mercury emissions resulting from the use of amalgam in dentistry?”

It’s becoming obvious to municipal authorities that they are facing a problem concerning the management and elimination of wastewater sludge contaminated with mercury. In fact, whether incinerated or disposed of in landfill, wastewater sludge containing excessive amounts of mercury heavily contributes to the contamination of our environment. The natural elimination of mercury is slow: this is why this toxic substance is accumulating in ecosystems. To solve this type of ‘end of pipe’ environmental problem, municipal authorities have decided to target mercury emission at its roots.

The purpose of this paper is to come to a global understanding of this problem. It explains the present environmental situation and sketches the legal and legislative context of these new by-laws and guidelines. The paper includes an analysis of these new regulations as well as an overview of products and services available in Canada and North America concerning amalgam separation and amalgam waste containing mercury.


From a strictly environmental perspective, Canadian federal authorities consider mercury as one of the most harmful pollutants to the environment. They declared that mercury contamination should be eliminated or drastically reduced.1 As time goes by, mercury concentration accumulates in the aquatic food chain, becoming a health threat for birds, mammals and human beings eating contaminated fish. Environment Canada has confirmed that it’s now proven that atmospheric mercury contamination can travel major distances.2 Finally, mercury contamination still represents a major problem for many ecosystems and the Canadian government considers the elimination of mercury contamination and emissions a priority.

In the United States, particularly for Northeastern states of the country, the Environmental Protection Agency (EPA) is quite concerned about the level of mercury contamination. In its publication ‘Fact Sheet on Mercury’, the EPA says that between 1993 and 1998 ‘advisories’ concerning mercury contamination level for lakes and rivers increased 115%; between 1997 and 1998, it increased 8%. More significantly, states such as Maine, Vermont, New Hampshire, New York and Massachusetts fell under advisories covering 100% of their lakes and rivers. Five of the eleven states hit by advisories for all lakes and rivers were located at the Quebec and Ontario borders while nine of those eleven states are north-eastern states.3

These facts on the environmental situation in Canada and in USA brought authorities to modify former by-laws or adopt new ones concerning mercury emissions from dental clinics. Data are showing if not growth, at the very least an important mercury contamination in many ecosystems. This situation could be symptomatic of an efficiency problem related to environmental policies. It shows that there were obvious weaknesses in the way by-laws and environmental standards concerning mercury were implemented.

For the MUC territory, data showed that mercury emissions from incinerated wastewater sludge exceeded the Canadian standard. The MUC average emission reached 110 (g/m3, which is 157% over the 70 (g/m3 Canadian standard.4 Studies and analyses from the MUC brought them to conclude that mercury waste produced by dental clinics could represent more than 25% of the total amount received at the municipal water treatment station.5 However, these conservative data may even underestimate, and from up to half, the mercury emissions from dental clinics.

According to MUC specialists, the water treatment station system can only capture 50% of the mercury from the wastewater and its efficiency is reduced when treating dissolved mercury.6 Wastewater stations were initially conceived to protect rivers from organic pollutants and phosphate contained in the treated water. They were not designed to treat heavy metals like mercury. And part of these heavy metals are trapped and accumulate in the sludge.

While the CRD case is similar to the MUC’s, the Toronto situation was quite different. Toronto’s officials had been working on this by-law for some time. But the Walkerton water scandal and the environmental crisis brought on by severe casualties related to neglectful water management triggered Toronto City Council to adopt a new and tougher by-law. In fact, the new by-law sets levels 10 times lower than most cities, from 0.1 to 0.01 mg/l.7


It’s important to mention that environmental by-laws and standards concern mercury emissions from the use or handling of materials containing mercury only. In dentistry, this relates to dental amalgams. Authorities, therefore, are not targeting the use of amalgam in dentistry per se, but rather the way it is used in regards to official environmental requirements (emission levels). Existing by-laws are almost exclusively aimed at mercury emissions in the water sewage system or as solid waste.

From a legal point of view, and specifically for municipalities where mercury legal limits were under 0.05 mg/l, the legality of dental clinics was highly questionable. On its territory, the MUC concluded that sampled clinics exceeded the official mercury threshold in wastewater by two to 16 times.8 Since dental practices do not vary dramatically in North America from one province or state to another, it can be extrapolated that the dental community at large is exceeding legal limits of mercury in wastewater where they are set at 0.05 mg/l and under.

What also pushed the MUC to toughen its legislation was the adoption of the Action Plan concerning Mercury set forth by the Conference of New-England States and Prime Minister of Canadian Eastern Provinces held in Fredericton in 1998. The Action Plan recommends a 50% reduction in mercury emissions by the year 2003. The Canadian Council of Ministries of Environment created a Canadian-wide standard (CWS) for mercury with a specific section for mercury emissions generated from the use of mercury in dentistry. The CWS refers to the need for dental clinics to use amalgam separators with an efficiency level superior to 95%. The standard provides to all Canadian provinces and municipalities a minimal framework to harmonize the adoption of new policies.

Significantly for the MUC and the CRD, legal emission levels were not modified in their new adopted by-laws. They decided to impose on dental clinics specific measures assuring that their mercury emission could meet the legal limit or an acceptable limit for the protection of the environment. MUC maintained its limits to 0.05 mg/l, while CRD kept its 0.02 mg/l mercury emission level.9 Finally, the MUC and the CRD have modified their former by-laws imposing the use of ISO certified amalgam separators.

However, the City of Toronto chose a distinctly different strategy from the MUC and the CRD. Toronto officials made the decision to lower the former mercury emission level of 0.1 mg/l to 0.01 mg/l, to bring it ten times lower. Considered as generic, the new level limit concerns all sources of mercury emissions for the Toronto area. For dental clinics, the City’s guideline is mentioning that to approve their Pollution Prevention Plan (P2), the use of amalgam separator ISO certified or meeting the Canadian Wide Standards (CSW) will be compulsory. Dental clinics will have to present their P2 plan not later than January 1st, 2002 and install ISO or CSW11 certified amalgam separator for July 1st, 2002.

By-laws or guidelines from Toronto, CRD or MUC also target the legal obligations for the appropriate management of waste coming out from dental clinics. They specify requirements for the waste transport, shipping and recycling process mentioning that those operations should always meet provincial, federal or states environmental requirements.


Scandinavian countries were the first worried about mercury emission coming from dental clinics after having reduced mercury emissions from industrial sources. Sweden started its studies in the 1970s and was a pioneer in the field to initiate action to reduce toxicity from dental clinic emissions. The Swedish EPA, the Swedish Dental Association and suppliers made an agreement in 1979 which was totally enforced by 1985 concerning:

– The annual cleaning of drain traps;

– The installation of an amalgam separator with a minimum efficiency of 95% for mercury contaminated water in dental clinics;

– Good practices management for waste disposal in dental clinics.

In Germany, dental clinics must be equipped with amalgam separators with a minimal efficiency of 95% for all water sent to sewage systems.13 Denmark has one of the stricter standards and policies concerning mercury.14 According to the law, the sale of mercury or products containing mercury is prohibited. The use of certain types of products in which amalgam was included was permitted for a limited time. However, the use of amalgam has been prohibited since 1995. Again, special use of amalgam was further tolerated until 1999. Even though, due to the removing of patient old amalgam, the use of amalgam separators became compulsory for all dental clinics in Denmark.


Despite differences between municipalities’ by-laws, the strategy behind them is similar. Concerned municipalities as well as the CCME made the decision whether to impose or recommend the use of ISO or CWS certified amalgam separators with a 95% efficiency level. The strategy is to impose a measure considered efficient enough to assure that legal or environmental objectives will be meet, beside the legal limits for mercury emissions. It also explains why the obligation to use ISO 11143 certified technologies allows authorities to implicitly or explicitly wave out dental clinics to meet the generic level.

The strategy is profitable both for municipalities and dental clinics targeted by environmental policies for mercury emissions. Imposing or recommending standards and technical solutions avoid municipalities to spend resources in controls and legal procedures. For dental clinics, it avoids disruption, functional and economic losses caused by necessary control measures that authorities should apply to control equipment devices and their efficiency. On the dentist’s end, the clear obligation to use amalgam separators ISO or CWS certified ensures that he does not have to worry about clinic’s mercury emission conformity with the generic level limit. And more important, dental clinics will get a better guarantee that their efforts will bring positive results for the environmental protection.

The policy management referring to standards and certifications is part of a new generation in environmental policies aiming for a better efficiency in their results. This strategy completes a first generation of environmental policies where generic limit levels were generally imposed for a wide list of contaminants. And beside exception, those limits were addressed for everybody in every case. Even if it was, and is still useful, the first generation of environmental policies were not complete or sufficient to meet fixed environmental goals and needs.

Moreover, the new strategy referring to standard and certification bring a dynamic impulse for the evolution in equipment solutions. In parallel to the governmental decisional process, officials, members or comities of standards organisations as ISO or other national organizations, keep working on the process to analyse possible technological progresses for concern standards (in dentistry, transport, engineering etc.). In other words, by-laws referring to standards as ISO 11143 can be improved by themselves without the need for governmental authorities to constantly review regulations and policies.


The ISO 11143 was created in 1999, by the International Organisation for Standardization (ISO). ISO is a world-wide federation of national standards bodies from some 130 countries, one from each country. ISO is a non-governmental organization established in 1947. The mission is to promote the development of standardization and related activities in the world with a view to facilitating the international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity. ISO’s work results in international agreements, which are published as International Standards.15

The ISO 11143 standard specifies requirements for amalgam separators used in connection with dental equipment in the dental treatment centre. It specifies the efficiency of the amalgam separators in term of the level of retention of amalgam based on a laboratory test and the test procedure for determining this efficiency. It also includes requirements for the safe functioning of the separator, marking, and instructions for the safe functioning of the separator, instructions for use, operation and maintenance.16


When by-laws were adopted by the MUC, the City of Toronto and the CRD, three manufacturers were offering ISO 11143 certified equipment for the Canadian market. However, in Canada and the US, we find other manufacturers and suppliers offering amalgam separators meeting the 95% efficiency level asked by the CWS for mercury emissions. It is important to take note that without an ISO certification those technologies or equipment do not meet the requirement asked by the MUC or the CRD.

We already noted that the MUC, the City of Toronto and the CRD will ask and do verifications concerning waste management procedures for amalgam wastes collected from dental clinics by required equipment. Municipal authorities will verify that the transport, shipping and recycling services offered always follow legal requirements where it applies. To respond to those requirements, manufacturers and suppliers offer environmental services for the transport, shipping, storage and recycling of amalgam waste. We must mention that those environmental services are not systematically included in the cost to acquire amalgam separators.


What looks like a sudden movement, when municipalities adopted their new by-laws on mercury emissions from dental clinics, was in fact the result of a long process. On the environmental and legal side, authorities wanted to target the mercury emission problem and their inability to manage efficiently enough mercury emissions in the water and in the atmosphere. However, the use of mercury in dentistry in itself does not represent an environmental problem as long as mercury emission and waste are managed properly with the help of appropriate technologies and services.

Actually, except for Toronto, the CRD and the MUC, municipal by-laws do not specifically target mercury or amalgam waste coming out of dental clinics. However, there is always a legal generic level for mercury emission in municipal sewer systems. In Canada, from one province to the other, the legal generic level for mercury can vary considerably. For example, in Quebec, mercury emission is fixed to 0.05 mg/l and under for most of the municipalities. But it is meaningful that studies and samplings made by the MUC authorities demonstrate that dental clinics’ mercury emissions, were constantly two to 16 times over the mercury level of 0.05 mg/l. Owners of dental clinics should be aware of their mercury emission when the applying municipal level is 0.05 mg/l and under.

Lately, in Canada, the concern for the water resources management is growing up. The Quebec government held important public debate on the water management issue last year. The Walkerton Affair more than everything else triggered a major questioning on how authorities were facing serious difficulties with their water policies. And since Walkerton, across Canada, every week brings case of alarming environmental situation concerning water management. The actual context and expoxed facts should bring dentists or dental clinic owners everywhere in Canada, to question their environmental situation about the mercury issue.

For dental clinic owners located in the CRD, MUC or Toronto area legal requirements are clear. Their clinic will have to be equiped with ISO or CWS certified amalgam separators before a limit date fixed by new municipal by-laws. And as waste generators, dental clinics are responsible for the entire waste management of their waste containing mercury or other products classified as hazardous. Moreover, it is important for dental clinics to use appropriate equipment but also to be assured that waste management services related to mercury waste are in conformity with legal requirements (municipal, provincial or federal).OH

Yves Hennekens is an environmental issues consultant. On the climate change issue, his clients are SNC-Lavalin, The Alliance of Manufactureres & Exporters, the Fondation qubcoise sur l’environment. On the mercury issue, he has worked for manufacturers and suppliers of dental equipment as well as for a dental association. He has worked as political advisor for the Minister of the Environment in Qubec.

Oral Health welcomes this original article. Views expressed are those of the author and do not necessarily reflect those of Oral Health.


Toronto: http://www.city.toronto.on.ca/involved/wpc/nbylaw.htm

Capital Regional District (Victoria):


Montreal Urban Community:


Canadian Council of Ministers of the Environments:

Mercury Canadian Wide Standard



ISO: Comit ISO 11143:

ISO/TC 106/SC 6 Dental Equipment:

Dr. Hans-Peter Keller

Aussenstelle Pforzheim des DIN

Westliche Karl Frieddrich-Strasse 56

DE-75172 Pforzheim


1. Bulletin d’Environnement Canada – Rgion de I’Atlantique, A propos des produits chimiques toxiques, Volume 3, Num6ro 1, Janvier 1998, ISSN 1206-5463, www.ns.ec.gc.ca/epb/newsletters/toxchem/ toxic-chem6_f.html

2. Environnement Canada, Le mercure au Canada Atlantique: Rapport d’etape, p. 3 www.ns.ec.gc.ca/ reports/mercury-98-09-23-summary-f.html

3. US EPA, Fact Sheet on Mercury

4. Action Plan for Mercury, Conference of New-England States and Prime Minister of Eastern Provinces at Fredericton in 1998

5. Vu les diffdrentes etudes realisees ci travers le monde (cf Tableau 2), l’estimation retenue est le chiffre moyen de 152 mg/j/dentiste. Cette moyenne aboutit a une charge annuelle de 45.6 kg de mercure, soit 25% de la charge recue a la station d’epuration. CUM, Document publie en mai 1999.

6. CUM, Herve Loge, Document publie en mai 1999.

7. Toronto By-Law No.457-2000, To regulate the discharge of sewage and land drainage.

8. Document de presentation presente a la Commission de l’environnement, Seance publique du 25 avril 2000, sur le projet de modification au reglement 87 de [a CUM; et Document de la CUM publie en Mai 1999.

9. CRD, By-law No.2830

10. City of Toronto By-law No. 457-2000, p. 18, Compliance Program, 7. (3), The Commissioner may issue an approval for a compliance program for an industry to discharge an effluent that does not comply with Table 1 and Table 2 of this Bylaw such approval to be accordance with guidelines therefore adopted by the City from time to time.

11. Prior to install CWS certified equipment, the City of Toronto will have to test the amalgam separator’s efficiency. Author’s note.

12. CUM, Herve Loge, Document publie en mai 1999.

13. Verordhung Ober Anforderungen an das Einleiten von Abwasser in Gewcisser und zurAnpassung derAnlage des Abwasserabaabenaesetzes, mars 1997, Anhang 50.

14. Loi No. 520 du 1994-06-09, “Order on Prohibition of Sale of Mercury and Mercury-containing Products”, effective depuis le 1994-07-01; cf. annexe 2, CUM, Herve Loge, Document publie en mai 1999.

15. Introduction to ISO, http://www.iso.ch

16. ISO, Joseph Martinez, Information officer, 8 decembre 2000.

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