Management of mercury legacy from dental amalgam in waste water

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Mercury, Hg, is a potent neurotoxin that bioaccumulates in fish and shellfish, making it a global pollution concern. The United Nations Environmental Program (UNEP) has stated that Hg and its compounds are serious risks to human health and the environment. This issue a major environmental priority: in 2017 UNEP brought into force the 'Minamata Convention,' a global treaty to "protect human health and the environment from the adverse effects of mercury." Through this treaty, UNEP sets out to phase down, phase out and eliminate global Hg use. Dentistry is a major source of Hg; the metal makes up 50% of the 'dental amalgam' used in traditional silver fillings. Although dental amalgam is being replaced by plastic and ceramic substitutes; this is a slow process and in the developing world it remains the principal dental filling material. Furthermore, a 'legacy problem' remains from its uncontrolled disposal over the last 150 years. In some developed countries, dental surgeries are equipped with 'dental amalgam separators'; but elsewhere discharge of this waste into municipal sewers is still common. The release of this waste into municipal facilities creates a complex pollutant legacy as heavy amalgam waste settles in sewerage pipes, becoming accreted in anaerobic sludge. UNEP estimates that thousands of tonnes of Hg from dental amalgam enter waste streams each year and that this is a significant problem in developing equatorial and tropical countries where uncontrolled waste disposal is widespread, as at the higher temperatures in these regions bacterial action increases the deleterious effects of Hg, by forming the exceptionally hazardous bio-accumulating neurotoxin, methyl mercury. This project will develop and grow a bespoke research team, with partners in the UK and India, to identify a strategy for the quantification of Hg from dental amalgam present in waste-water systems. The strengths of the team comes from a combination of highly skilled 'task-specific' scientists in the Research Institutes formed by the Council of Scientific & Industrial Research (CSIR) with unique knowledge and expertise in analytical systems for the detection and quantification of mercury. CSIR scientists will work and share specialist knowledge with colleagues in the Department of Chemistry at the University of Sheffield, UK. The team also has the invaluable strategic support and expressed desire for collaboration from UNEP and the World Health Organisation. Both these organisations have identified India as an area of 'environmental interest and required action' for this pollution pathway; and in this way we are combining the expertise of international collaborating partners that are operational in an 'at risk' location. The presidency of the Indian Dental Association has joined our collaborative team and will provide guidance, expertise on 'at-risk sites', essential national advice on local and national professional and political resources, and possible future funding opportunities.This application seeks to develop this powerful scientific consortium and facilitate a proof of concept study to optimise sensitive mercury detection methods developed by CSIR-CSMRI. The work packages we have developed are designed to meet specific objectives: (i) to further develop and refine this test and other sensitive methods to identify and quantify Hg content in waste water. (ii) to identify target sites where amalgam residues accrete inside waste water pipes. (iii) to develop water sensing capabilities to test 'down-stream' from a contaminant source. (iv) to electronically automate testing for the presence of mercury or methyl mercury in water or accretions in pipes.This initial programme of activities will enable us to develop the consortium and apply for more comprehensive, long-term, funding to address the challenges of this environmental pollutant pathway in an impactful way.