Mercury and the environment

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From 28 July until 2 August 2013, around 1,000 experts from around the world will attend the 11th International Conference on Mercury as a Global Pollutant (ICMGP) in Edinburgh. Held periodically for over the last 18 years, it has become the pre-eminent international forum for presentation and discussion of scientific advances concerning environmental mercury.

This year’s conference is of particular public importance, as this will be the year that sees the launch of the United Nations Environment Programme Global Legally Binding Instrument (UNEP Global LBI) on Mercury, which is a legally binding convention directed at reducing global mercury pollution.

Mercury is a naturally occurring element found in all parts of the environment (air, water, soil and rocks) and exists in several different forms, including metallic mercury, and both inorganic and organic mercury compounds. It is widely found in a number of everyday uses including: barometers, batteries, electrical appliances, medical applications, light bulbs (energy savers) and in amalgam dental fillings.

So why is mercury of such great concern? Mercury and its compounds are very toxic to wildlife, plants and micro-organisms. Persisting indefinitely (in various forms) in the environment, organic compounds of mercury can build up to very high concentrations in organisms, including those at the top of the food chain (such as mammals and fish). As humans are also at the top of the food chain, eating contaminated animals and other foods can also lead to accumulation of mercury in the body and result in health effects such as damage to the nervous system, lungs and kidneys. Exposure to mercury can also occur through breathing in mercury vapours or following an accidental release.

Mercury is released naturally from the Earth’s crust and from natural events such as volcanic eruptions. The main man-made sources of mercury to the environment are from:

  • coal combustion;
  • waste incineration;
  • chlorine manufacture;
  • gold mining;
  • the oil and gas industry;
  • metal production;
  • dental surgeries and crematoria;
  • hospitals and clinics;
  • industrial processes using mercury and its compounds.

Minamata Convention on Mercury

In February 2009, the Governing Council of UNEP adopted Decision 25/5 on the development of a global legally binding instrument (LBI) on mercury. On 19 January 2013, governments agreed to the text of the global LBI on mercury and gave rise to the Minamata Convention on Mercury.

Following the conclusion of the negotiations, the text will be open for signature at a diplomatic conference, which will be held in Minamata and Kumamoto, Japan, from 9-11 October 2013.

The convention provides controls and reductions across a range of products, processes and industries where mercury is used, released or emitted. These measures cover the range from medical equipment and energy-saving light bulbs to the mining, cement and energy supply sectors and the export and import of the metal and safe storage of waste mercury. Pinpointing populations at risk, boosting medical care and better training of health care professionals in identifying and treating mercury-related effects will also form part of the agreement.

Governments have agreed on a range of mercury-containing products whose production, export and import will be banned by 2020, these include: batteries, certain types of compact fluorescent lamps (CFLs), soaps and cosmetics; and a phase-down of the use of dental fillings using mercury amalgam.

The treaty will control mercury emissions and releases from various large industrial facilities, ranging from coal-fired power stations and industrial boilers, to certain kinds of smelters handling, for example, zinc and gold. Waste incineration and cement clinker facilities are also on the list for control.

Mercury impacts in Scotland

Currently, the emissions and handling of mercury from an environmental perspective is very tightly controlled by a wide variety of EU legislation, which has been transposed into domestic legislation, and which we at SEPA enforce in Scotland (and these controls are likely to get even tighter over time).

So how big a problem is mercury in Scotland? The majority of Scotland’s mercury emissions come from industrial sources such as power generation, industrial activities, water treatment, waste management and the oil and gas sectors. However, to provide some perspective on Scotland’s impact on global mercury emissions, the total global man-made created emissions of mercury to the atmosphere in 2010 are estimated to be around 1960 tonnes. Scotland’s total emissions during this time were under 0.323 tonnes (from regulated sources) of the UK’s total of 3.3 tonnes. Therefore mercury tends not to be a substance of concern in Scotland with the relatively limited emissions to the environment.

However, while mercury emissions from Scotland are relatively small-scale, due to its nature as a persistent and global pollutant, we must continue to ensure as far as possible, mercury emissions are limited, its use is reduced, and exposure to mercury from the environment is minimised. The UNEP Minamata Convention is a significant step towards achieving these goals.

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