11 June 2012

Curbing mercury pollution in nature

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A new report estimates that 70% of the European ecosystem is endangered by mercury pollution, a good proportion of which comes from dental repairs. Without further EU policy action and research, reducing such pollution may not be easy 

Since the amalgam used in dental work is now the second-highest source of mercury within the EU, reducing dentists’ use is crucial, according to a new EU environmental report including extensive data on mercury use and pollution dental and button battery sources. Gathering of these findings is taking place alongside the EU-funded ESPREME project, which aims at establishing a pan-European map and economic models of heavy metals emission of mercury, cadmium, lead, arsenic, nickel and chromium.

The new draft report, due to be finalised in June, estimates that the average EU mercury demand for dentistry was between 55 and 95 tonnes in 2010. The report also finds that dental amalgam, including that reaching the environment through burials and cremations, contributes between 21% and 32% of overall EU mercury emissions to air and 9% to 13% to surface water. 

Eamonn de Barra, a lecturer in biomaterials at the University of Limerick, Ireland, emphasises the need to reduce such mercury pollution through EU laws and directives: “Despite improvements, there are still environmental concerns regarding end of life of such materials, which combined with increased numbers of cremations, causes local concentration effects of gaseous phase mercury emissions.”  He quotes mercury encapsulation and substitute restorative materials as two of the avenues currently explored to reduce mercury release. Typical restorative materials include glass and resin-based composite and ceramics.

Because mercury makes up about half of dental amalgam, the report estimates that 45 tonnes of mercury ends up as effluents alongside dental chairs. Only a fraction is captured and treated as hazardous waste in compliance with EU directives, according to the new report.

“I doubt if the report will change much unless significant new evidence is provided, but it is clear that different countries have different positions,” says Shailendra Mudgal, Executive Director of the Paris, France-based environmental and sustainable development consultancy BIO Intelligence Service (BIO IS), which produced the report for the European Commission, DG Environment. “Some countries have economic concerns, others have environmental/health concerns, and some have both.”

The report compares the economic costs of the various options for reducing mercury pollution in the environment. It concludes that the most effective way of reducing the environmental impacts of dental use would be to improve enforcement of EU waste legislation and to ban the use of mercury in dentistry. The study also recommends banning the sale of button batteries within the EU “Button batteries are not a big issue because industry is working on it already,” said Mr Mudgal.

In addition, the reports points to the added burden in that mercury has accumulated in the environment over many years, despite the adoption in 2005 of an EU Mercury Strategy “to reduce mercury levels in the environment and human exposure, especially from methyl mercury in fish”.

Neil Ward, Professor at the Department of Chemistry, University of Surrey, UK, comments: “It is vital that these EU directives are supported by funding for more research to address existing mercury exposure, so that remediation technologies are fit-for-purpose to address different types of mercury pollution and to alleviate human health problems from mercury exposure.”

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