Management of mercury legacy from dental amalgam in waste water

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.

This proposal is a unique programme, sustainable beyond this application, of research activity that focuses on the historical pollution pathway and the bio-accumulation of mercury from dental amalgam.

The primary impact arising from this proposed programme is the creation of a unique and fit-for-purpose scientific research consortium that is equipped to manage this challenge with a measured escalation of activity as the programme of work develops. This will generate further impact through the acquisition and development of scientific knowhow that will be directly translatable to a practical use for the identification and quantification of mercury waste and methods for its subsequent remediation; importantly also outside the remit of dental amalgam and to manage mercury contamination in water-ways from other industries. Given the uniqueness of the challenge and the nature of the knowledge that it will generate, we anticipate that it will have direct and indirect environmental, healthcare and socio-economic impacts far beyond academic research at multiple levels:

1-Creation of a bespoke research community specially tailored to meet this environmental challenge. This consortium benefits from the direct participation and support of a multi-disciplinary team that is suited to impact at a scientific level (Core chemical research in UK and CSRI institutes in India); dental community (PI in the UK and the Hon Sec. General of the Indian Dental Association) and the political and policy engagement from the WHO & UNEP- Identified through this proposal and the letters of support.

2-The scientific communities that are engaged in the management of mercury pollution, directly or through UNEP: Minamata Convention and the Mercury Partnership; will benefit from the publication of high quality peer-reviewed papers in key journals, attracting wider interest from other disciplines that may have scientific and technological related unmet needs.

3-Identification and Remediation Strategies - Through this scientific academic research activity, and related interactions with the dental profession and policy makers, it is planned to reach out to other key stakeholders to establish a programme of 'Identification and Remediation Strategies'. Parallel activities by the UK group are validating, through a proof-of-concept study, a novel remediation strategy. We are currently planning activities beyond this initial seed-corn funding to apply for GCRF that merges these work streams and create an impactful substantial work programme that will address the challenge in its entirety.

4-Knowledge exchange activities are key to this programme, especially as the project matures with tangible solutions, to be applied used across the world to address this particular challenge and mercury pollution of water ways, arising from other mercury contaminants.

5-Generation of IP for the research group resulting directly from the technologies developed and validated. Also, the creation of strong scientific world-wide networks with the WHO and UNEP with UK leadership. This will enable the formation of new research and development partnerships to better and more rapidly exploit scientific advances for societal, environmental and economic benefits.

6-Policy making and Strategy planning - The group will be able to make a valuable and environmentally impactful contribution to the UNEP Mercury agenda, by influencing policy and strategic planning. This is evidenced by the interest and support demonstrated by WHO and UNEP in this programme (letters of support).

7-New job creation in the scientific communities associated directly with this project as a result of personal endeavours and indirectly as the technologies are used and applied world-wide as part of a remediation strategy.

Further detail is provided under the "academic beneficiaries" section of the proposal.