Environmental Impacts of Mercury Exposure

What is mercury?

Mercury (Hg) is a naturally-occurring chemical element that can be found in three forms; elemental (metallic) mercury, inorganic and organic mercury.

Elemental mercury is a shiny, silver-white liquid metal at room temperature. It is often referred to as quicksilver and evaporates to form invisible, odourless toxic mercury vapour.

Inorganic mercury is where mercury has combined with other elements. Mercuric sulphide contains sulphur, mercuric oxide contains oxygen and mercuric chloride contains chlorine. These compounds are mostly white powders or crystals.

Organic mercury is found naturally in the environment. It is released from the earth’s crust and can be found in fossil fuels, soil, rocks and volcanoes.

What is mercury used for?

Before it was realised that mercury and its compounds are extremely toxic, the chemical was widely used in a host of industrial and domestic products and processes – from batteries and auto switches to CRTs and dishwashers, to HVAC equipment and lamps of all types. For many years it was an important additive in paints, cosmetics, pesticides and rubber flooring.

Even today when its toxic properties are much better understood, it remains an important chemical in a host of manufacturing processes, including the production of chlorine, cement, caustic soda and sulphuric acid, and it is used or emitted in significant quantities in the likes of power generation and dental care.

Mercury is also commonly found in thermometers, barometers, mercury switches, electrical relays, fluorescent lighting and even lighthouses.

How does mercury get into the environment?

Mercury is introduced into the environment in many ways. It can be emitted into the air naturally from volcanoes, the weathering of rocks, forest fires and soils. It is also released into the air from the burning of fossil fuels and medical or general waste. Natural processes such as the evaporation of ocean water can also release mercury into the environment.

Human activity is the main cause of mercury releases, particularly the use of coal-fired power stations, residential coal burning for heating and cooking, industrial processes, waste incinerators and it can also enter the soil from fertilizers, fungicides and from solid waste i.e. thermometers, light bulbs or electrical switches.

How long can mercury last in the environment?

Mercury persists in the environment for long periods of time by cycling back and forth between the air and soil, all the while changing chemical forms. Atmospheric lifetimes of inorganic elemental mercury are estimated to be up to two years, while organic methylmercury may stay in the soil for decades. Mercury is never removed from the environment, it is just moved to other locations and eventually buried under soils and sediments.

What are the health impacts of mercury exposure?

The presence of mercury in the environment does not always lead to exposure. For it to cause any adverse health effects you must come into contact with it.

You can be exposed to mercury by breathing or ingesting it, or by coming into contact with it. Following exposure to any chemical, the adverse health effects you may encounter depend on several factors including the amount to which you are exposed to, the way you are exposed and the duration of exposure.

Guidance and information on workplace exposure limits can be found in the HSE EH40 Regulations. Exposure to excessive levels of mercury can permanently damage or fatally injure the brain and kidneys. Elemental mercury can also be absorbed through the skin and cause allergic reactions.

How can I monitor mercury?

Occupational exposure to mercury can occur in several workplaces that use mercury, such as in factories making electrical equipment or thermometers, chemical processing plants and dental practices. Safe levels are enforced to protect employees who may be exposed to mercury at work.

The Ion Science Mercury Vapour Indicator (MVI) can detect mercury in just three seconds and, unlike other technologies, does not rely on waiting for gold film to regenerate. Fast and accurate, the MVI provides continuous readings and offers two detection ranges of 0.1-200μg/m3 and 1.0-1999μg/m3. These two ranges provide critical coverage for the EU-OSHA PEL at 100 ug/m3 and the IDLH at 1,000 ug/m3.

A high-performance pump ensures fast indication and recovery and the instrument’s audible alarm and large digital display clearly indicate the levels of mercury present. With ultimate portability, excellent battery life and fast recharging, fewer analysers are needed on-site which reduces the cost of monitoring. An optional data logger is also available. Ergonomically designed for simple, one-handed operation, the MVI is the ideal survey unit for rapid and reliable mercury detection.

The MVI is available to hire or buy from Shawcity. For more information or to request a free demonstration contact info@shawcity.co.uk or call 01367 899418.