Minamata Convention: What's it all about?

This article was originally published in the ADA's News Bulletin, November 2022

The Minamata Convention on Mercury is a United Nations Environment Program (UNEP) initiative, the objective of which is to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds. The Convention covers the life cycle of mercury by controlling and reducing mercury across a range of products, processes and industries. This includes controls on mercury mining, the manufacture and trade of mercury and products containing mercury, disposal of mercury waste and emissions of mercury from industrial facilities.

Mercury can produce significant neurological and other health effects, especially in unborn children and infants. The UNEP mercury program was developed in the mid-2000s to address these concerns, including voluntary actions by governments as there had been a notable increase in mercury in the food chain. However, in 2009, the Governing Council of UNEP (later renamed the United Nations Environment Assembly) agreed that voluntary actions had been inadequate, and agreed the need for additional initiatives. To this end, a global Legally Binding Instrument (LBI) was established in 2013 following the work of an Intergovernmental Negotiating Committee that produced the Minamata Convention.

The text of the Convention was adopted on 10 October 2013 in Minamata City, Japan. Minamata was symbolically selected because of its history of severe mercury poisoning among the population. 
Neurological symptoms began to appear in 1956, and became known as ‘Minamata disease’. The feline
population was first affected, and was given the name ‘dancing cat fever’. It was eventually found that the Chisso Corporation had discharged an estimated 27 tons of methyl mercury, used in acetaldehyde production, into Minamata Bay between 1932 and 1968, resulting in fish poisoning. One reference, citing the Japanese government, states that 2,955 people contracted Minamata disease and 1,784 people have since died. Children of affected parents were born with severe deformities, including gnarled limbs, intellectual disability, deafness and blindness. For many years Chisso denied any responsibility, and legal action is ongoing.

At the time of writing this article, the Convention has been signed by 128 countries and the European Union, including Australia in December 2021, and are therefore bound by international law to adopt the provisions of the Convention. Strategies to meet the objectives of the Convention include controlling the supply and trade of mercury, controlling mercury-added products and manufacturing processes and regulating artisanal and small scale gold mining. The Convention also addresses emissions and releases of mercury, and environmentally sound interim storage of mercury and mercury wastes. In 2018, the UNEP published its Global Mercury Assessment.

It was noted that ‘mercury emissions to air from anthropogenic sources in 2015 quantifies global emissions from 17 key sectors at about 2,220 tonnes’, and that smaller anthropogenic sources contribute ‘in the order of tens to hundreds of tonnes per year’. The Convention prescribes a ‘phase-out’ date for a wide range of mercury-containing products. For example, certain batteries, relay switches and compact fluorescent lamps had a phase-out date of 2020. Some products containing mercury products are excluded, such as those for research, calibration of instrumentation, for use as reference standard, and vaccines containing thiomersal as preservatives.

Dental amalgam is specifically cited in a table in Annex A, Part II of the Convention. In contrast to most other mercury- containing products and processes, the Convention allows for a ‘phase-down’, rather than a ‘phase-out’, approach, recognising that many countries depend on amalgam as their main restorative material and a suitable alternative has yet to be identified. In its submission to the Australian Department of the Environment and Energy (DEE), the Australian Dental Association (ADA) essentially supported the ratification of the Convention.

Annex A, Part II requires countries (‘Parties’) which have ratified the Convention to ‘…take into account the Party’s domestic circumstances and relevant international guidance and shall include two or more of the measures from the following list:’ This list specifies nine measures, which can be divided into five main themes: disease prevention and health promotion; dental restorative material research; dental education; financial incentives; best management practices. The text and implementation of the Convention are kept under regular review by the ‘Conference of the Parties’(CoP), and in 2022 the CoP added two more measures: eliminating the use of bulk mercury, and excluding or recommending ‘against the use of amalgam in deciduous teeth, patients under 15 years [of age] and of pregnant and breastfeeding women, except when considered necessary by the dental practitioner based on the needs of the patient.’

In 2019, the World Health Organization published its report ‘Future use of materials for dental restoration.’  The report provides global estimates, sourced from UNEP, on the major releases and pathways of mercury (tonnes/year) arising from dental amalgam: atmosphere, 50 – 70; surface water, 35 – 45; groundwater, 20 – 25; soil, 75 – 100; amalgam recycling, 40 – 50; sequestered (secure disposal), 40 – 50; total = 260 – 340. In the ADA’s submission to the DEE on ratification, it was noted that Australia’s share of mercury pollution attributed to dental amalgam waste in 2014-15 was approximately 1.3 tonnes out of 17.8 tonnes for that year, i.e. 7% of total output.

Members are encouraged to read the Minamata Convention and apply where relevant the principles embodied in Annex A, Part II, described above and referenced below. The ADA has three documents which support members in minimising the discharge of mercury into the environment. These are:

1. Policy Statement 6.11 Dental amalgam waste management

2. Guidelines for amalgam waste management and;

3. Guidelines for mercury hygiene.

It is imperative that waste amalgam is collected by an Environmental Protection Agency licensed entity for sequestering or recycling the mercury for a permitted purpose.

Key takeaways for dentists

Late last year Australia became party to Minamata Convention, which aims to protect the environment and humans from the adverse effects of mercury. The agreement has some specific requirements of dental practitioners so dentists need to consider a number of things:

(1) You should not be using any bulk form of mercury or amalgam; you should only access pre-capsulated amalgam.

(2) You should not be using amalgam in deciduous teeth, children under the age of 15, pregnant or breastfeeding women unless there are specific indications for its use in those groups.

Please reach out to the ADA via contact@ada.org.au if you need any further information on this issue, or go to ada.org.au/MinamataConventionRatification