Mercury: past to present

Dense, silvery mercury is the only metallic element to be liquid at room temperature. Its unique properties mean that it has had many uses over human history. However, it is also incredibly toxic and exposure comes with many risks.

This article gives a brief overview of mercury’s past and present uses, as well as the continued efforts to protect people from its harmful effects. Mercury monitoring is essential to these efforts and Enviro Technology are proud to have a range of options for this – find out more today.

Historical uses

Mercury was used in ancient Egypt, Rome, China, and India, often as a remedy or for ceremonial purposes. Termed “quicksilver” by ancient philosopher Aristotle, it quickly gained the attention of alchemists, who strove to transform it into other metals – ideally gold. While they were never successful, mercury could be used to extract gold. When applied, the mercury mixes with the sought-after element, allowing it to be collected. The mercury is then removed, leaving the precious gold.

From the 17th century, mercury was used in barometers and thermometers. Its physical properties – for example, consistent thermal expansion and high density – mean that it is ideal for making accurate temperature and atmospheric pressure readings. During and following the Industrial Revolution, mercury was used in industrial processes to produce synthetic chemicals and materials. Read a more detailed account of mercury’s historical uses here.

Current uses and pollution sources

Mercury remains prevalent:

• Thousands of tonnes are mined every year, despite the fact that mercury as an element cannot be destroyed and so mercury already in use can be recycled.
• Mercury is still widely used to extract gold. Artisanal and small-scale gold mining takes place in over 80 countries and employs 15 million people.
• Coal contains mercury and so power stations, industrial processes, and domestic heating systems that burn coal are responsible for mercury emissions.
• Cement production is estimated to generate 11% of global anthropogenic mercury emissions, with the coal and raw materials used containing mercury.
• Mercury is also present in some common products including batteries, electrical switches, lamps, dental amalgam (used in dental fillings), banned skin-lightening cosmetics, and pharmaceuticals.
• Once the above products become waste, mercury can be released from incineration, improper recycling, or in landfill leachate. Wastes from industrial processes may also contain mercury and need to be properly treated.

Protecting people from mercury

Globally – The toxicity of mercury has long been known, yet efforts to address mercury pollution were severely limited until events in a Japanese coastal city last century. From 1932 to 1968, a chemical factory in Minamata discharged liquid containing high levels of mercury into a local bay. The mercury built up in the fish the residents caught and, in 1956, the first case of what would be called Minamata disease was recorded. Since then, 70,000 more cases have been confirmed, with patients experiencing brain damage, paralysis, incoherent speech, and delirium.

While what happened in Minamata is not unique, and many people elsewhere have and continue to bear the burden of mercury pollution, the tragedy triggered concerted political action which brought about regular Global Mercury Assessments and the 2013 Minamata Convention. Ratified by 152 countries, the Convention aims to phase out mercury use in products; ban the opening of new mercury mines; and limit the emission of mercury into the environment.

Nationally – In 2017, the European Union (EU) adopted a new mercury regulation. This enables member states to meet the obligations of the Minamata Convention. It regulates movement of mercury in and out of the EU; specifies storage, disposal, and reporting requirements for mercury and mercury wastes; and restricts creation of new mercury products, industrial processes that involve mercury, and the use of dental amalgam. On withdrawal from the EU, we retained this regulation, but made minor changes to reflect the UK’s new context.

Mercury is also encompassed by more general UK legislation that protects workers and ensures responsible industrial activities. For example, to protect individuals in the workplace, mercury is subject to the Control of Substances Hazardous to Health Regulations (COSHH), which require employers to address risks posed to their employees from dangerous materials. There is also a Workplace Exposure Limit for mercury which should not be exceeded. However, at the same time, academics argue that a safe level of exposure to toxic mercury does not exist.

Wider harm is prevented by the requirement for any operations that might cause mercury pollution to have an environmental permit. This is where the Environment Agency specifies environmental and social conditions that must not be compromised by the proposed activities. As is clear from the above, this is of particular relevance to coal-fired power generation, cement manufacture, and waste incineration.

Mercury monitoring

It may be necessary to monitor mercury emissions in order to comply with an environmental permit. If so, Best Available Techniques (BAT) should be used. A component of the EU’s Industrial and Livestock Emissions Directive (formerly the Industrial Emissions Directive but updated to include intensive livestock farming), BAT are the practices agreed to be most effective and efficient at minimising emissions. BATs are linked to emission limits (BAT-AELs) which must be complied with unless otherwise agreed. For example, the BAT-AEL for mercury emissions to air from waste incineration is a daily average of less than 5-20 µg/Nm3 .

Enviro Technology’s solutions

Enviro Technology offers a portfolio of mercury monitoring solutions. We have market-leading systems for the continuous monitoring of atomic mercury (mercury on its own), as well as substances that include mercury (“total mercury”) in industrial gas emissions. Significantly, total mercury monitoring is now included in BAT. We also supply products by Tekran, who are specialists in trace gas mercury measurement. This is particularly important in checking gas before it enters the gas mains, as mercury is present in the natural state. We can also equip you with devices to calibrate these systems, as well as benchtop instruments for analysing samples in the lab. The latter can be automated for ease, efficiency, and accuracy of results.

If you’re looking for a mercury monitoring solution, get in touch with Paul Keeling today.

Read more: Find out about the different types of mercury here.