Mercury in the Environment

Photo by Tavo Romann, CC BY 4.0

What is it?

Mercury is a highly toxic metal that is liquid at room temperature and is commonly known as quicksilver due to its appearance. It is a naturally occurring element that can be found in the earths crust. In its natural form it typically does not present a risk to humans or the environment. However, humans have mined and used mercury for thousands of years and this has significantly increased the levels of mercury present in our air, water and soils.


How does mercury affect us and our environment?

Mercury exposure even in small amounts may cause serious health effects such as:

  • it may affect a child’s brain development in utero and into their developmental years
  • it may cause toxic effects on the digestive, nervous and immune systems and on lung, kidney, skin and eyes through prolonged or repeated exposure.


Mercury in the environment also has a significant impact on wildlife, including reducing the fertility of affected animals and also changing their behaviour.

In Europe the major sources of mercury release into the environment are through:

  • Industrial processes such as coal-fired power stations
  • Cement production
  • Iron and steel production
  • Waste incineration
  • Acetaldehyde and vinyl chloride production
  • Residential heating systems.


The chlor-alkali industry in Europe is no longer allowed to use mercury catalysts, hence it is not a big source in Europe but globally it is significant. Mercury released into the air can travel very large distances, and hence there are impacts associated with mercury even in areas where mercury usage or release is relatively low.

Products which may contain mercury include:

  • Dental amalgam
  • Thermometers
  • Light bulbs
  • Barometer
  • Blood pressure monitors

These are minor sources of human exposure to mercury, the primary human exposure route to mercury is through diet. Humans can be exposed to mercury through eating fish and shellfish. In general, the levels of mercury in fish depends on the size and age of the fish and on whether the fish is a predatory fish. Larger predatory fish such as shark, swordfish or tuna will tend to have higher levels of mercury. Herbivorous or smaller fish will have lower levels. It is for this reason that dietary advice, such as from the Food Safety Authority of Ireland (FSAI), recommends that certain vulnerable groups such as pregnant women limit their intake of fish such as tuna. However, the FSAI also stress that fish is an important element of a balanced diet.  


What is being done to tackle mercury?

Mercury is transported globally in the environment and as a result of this fact, global action on mercury is needed. This has come in the form of the Minamata Convention which was named after the worst historical case of mercury poisoning which occurred in the city of Minamata, Japan from 1932 to 1968, where mercury was released in the industrial wastewater from a chemical plant. The Minamata Convention, an international treaty to prevent the negative effects of mercury in the environment, was adopted and opened for signature on 10th October 2013. The EU and 86 countries signed the Convention on the first day it opened for signature. In total the Convention has 128 signatories. The Convention is a global legally binding instrument on mercury. The treaty is designed to protect human health and the environment from man-made emissions and releases of mercury and mercury compounds.

Even before the Minamata Convention came into effect, Europe had put in place extensive legislation to limit mercury use. A number of pieces of European Environmental Legislation exist to tackle the levels of mercury in the environment:

  • Regulation (EU) 2017/852 on mercury. This is the most important piece of European legislation on mercury and puts in place many of the requirements of the global Minamata Convention in Europe. The regulation covers the full life-cycle of mercury and controls import and export, as well as prohibiting the use of mercury in large industrial processes and in other activities, and ensuring the mercury waste is safely managed.   
  • Directive 2012/19/EU Waste Electrical and Electronic Equipment (WEEE Directive) regulated the separate collection and treatment of electrical and electronic equipment at end of life including mercury containing equipment and mercury containing components.
  • Directive 2011/65/EU on the restriction of the use of certain hazardous substances in electrical and electronic equipment (RoHS Directive) addresses the problem of hazardous substances in electronic equipment. For items to comply they must not contain more than 1000ppm mercury by weight in homogenous material.
  • The EU Industrial Emissions Directive controls the release of mercury from activities such as coal burning for energy generation (which is one of the biggest sources of mercury emissions in Europe).


EU legislation has banned the use of mercury in the following:

  • Batteries,
  • Thermometers
  • Blood pressure monitors
  • Barometers

Since July 2018 European legislation has also prohibited the use of dental amalgam (i.e. dental filling containing mercury) in the following cases:

  • In deciduous teeth (baby teeth)
  • In children aged under 15 years
  • In pregnant/breastfeeding women.

The regulations also require dental practitioners to minimise the levels of dental amalgam entering wastewater by using dental amalgam separators.


Management of Metallic Mercury Waste

Metallic mercury waste must be transported in accordance with Council Directive 2006/12/EC, Council Directive 2008/98/EC, Commission Decision 2014/955/EU and in accordance with current ADR Regulations for road, RID Regulations for rail and with IMDG Code for sea.

A Guidance Document for the Transportation of Metallic Mercury Waste for Hazardous Waste Collection Permit Holders is available here


Metallic mercury waste must be stored in accordance with Regulation (EU) 2017/852 on mercury.

A Guidance Document for the Storage of Metallic Mercury Waste for Hazardous Waste Transfer Facilities is available here.


Learn More

Check out the European Commission Mercury Webpage

Find out more about how mercury can enter our bodies

Find out more about the Minamata Convention on Mercury

Download Minamata Convention text and Annexes

Read about Mercury and Fish Consumption

Download EEA Report No 11/2018 Mercury in Europe’s Environment

Download Research Report No 307 Study on Usage and Waste Management of Amalgam Dental Fillings and Mercury-free Alternatives

Find information on industrial emissions of mercury in Ireland through the Irish Pollutant Release and Transfer Register reporting at: