Drops of mercury

Mercury: avoiding a hidden toxin

In Health and Healing, Health and Nutrition by Martin OliverLeave a Comment

Mercury-containing products are already banned in Norway and Sweden, and are subject to restrictive regulation in the EU and the US. In Australia, they are still promoted as safe, but the percentage of amalgam fillings placed has been shrinking. Proactive individuals can help make a difference by taking steps outlined here.


The only metal that is liquid at room temperature, giving rise to the name ‘quicksilver’, mercury is a remarkable substance that has fascinated humankind through the ages.

Its colourful and strange history includes an important role in the practice of alchemy. The alchemical substance cinnabar, a red powder containing mercury sulphide, was used by the wealthy in ancient China as a shortcut to achieving immortality. A mercury treatment for syphilis is considered to have been the cause of Mozart’s untimely death at the age of 35.

Health impacts

From ancient times, mercury was also known for its toxicity, being dangerous in both its liquid and vapour forms. From the 17th century to the early 20th century, hatters commonly used mercuric nitrate to prepare the felt used in hats. This led to the development of neurological disorders, and the saying ‘mad as a hatter’. Among hatworkers in Danbury, Connecticut, tremors were so common that they were known as the ‘Danbury shakes’.

Mercury releases by a chemical factory on the west coast of Japan led to ‘Minamata disease’, named after the city where it occurred. From 1932 to 1968, mercury bioaccumulated in seafood, leading to birth defects, poisoning and death. Thousands were affected.

Many informed people attempt to avoid mercury exposure where possible from sources such as fish, dental fillings, and industry. Mercury represents a particular risk for pregnant women, babies and children. It is neurotoxic, causes kidney and heart damage, and results in loss of IQ. Effects are multiplied synergistically when it is combined with lead or aluminium.

Low-level effects of mercury toxicity can be insidious. It accumulates in the organs, and to some degree blocks enzyme pathways and protein function, disrupting the neurological, endocrine, gastroenterological, and immune systems. Some types of people are genetically far more susceptible to harm from mercury.

Where is mercury coming from?

According to United Nations figures, about 70 per cent of mercury emissions are from human activities. The remaining 30 per cent from natural sources such as volcanoes. While usage in Western countries is dropping, in the developing world it has been steadily rising. South East and East Asia now represent about 40 per cent of global emissions.

Most human mercury air pollution comes from industrial sources. Coal, and gas-fired power stations are very close to the top of the list. Mercury is also released in cement manufacture. In these cases, it occurs as a natural contaminant in coal, gas and limestone.

Some older chlorine and caustic soda manufacturing plants still use a mercury-based chlor-alkali process, although many have changed over to the modern mercury-free membrane cell process. Rather bizarrely, tests on high fructose corn syrup (recently sneakily renamed by the American food industry as ‘fructose’) have identified mercury in low concentrations. This is probably coming from caustic soda used in the production process.


Another area of concern is some energy-efficient lighting. While a tiny amount of mercury vapour is found in compact fluorescent lamps, using higher-wattage halogen globes in their place will, paradoxically, result in greater mercury emissions due to the extra coal burnt to power them. Compact fluorescent lamps can also be recycled so that the mercury is recovered. LEDs, which are mercury-free and highly efficient, are the best solution. It is also found in fluorescent tubes, metal halide, and high-intensity discharge (HID) lights.

Where one of these is accidentally broken, safety recommendations warn that you should immediately open a window and then leave the room for 15 minutes so that the mercury vapour can disperse. Even better would be to require a warning insert to accompany these products.

Today, perhaps surprisingly, mercury is still being used in some new products on the market. These include a few types of medical equipment, thermometers, barometers, thermostats, switches, and some electronic components including relays and contacts. Collecting items with mercury for recycling prevents it from being released into landfills, or being burned in a waste incinerator, generating toxic ash that will typically have to go to a secure landfill.

In addition to some button batteries, older alkaline and carbon zinc batteries can contain mercury. Battery recycling facilities are available at Battery World, Aldi (for non-button batteries only), and some local councils. Mercury-containing lights can often be recycled by local councils, and at a range of other locations on the Recycling Near You website. For other items, talk to the council.


Vaccines on the whole are widely touted as mercury-free, but this is a little misleading. Traditionally they used very low levels of thiomersal, a chemical preservative that is about 50 per cent mercury. But it has been removed from some vaccines due to public concerns about its safety. The only two remaining vaccines in Australia that contain thiomersal are JE-VAX (for Japanese encephalitis) and Q-VAX (for Q fever). Neither of these are on the children’s vaccine schedule.

Cinnabar, in addition to its use in ancient China, is still part of Traditional Chinese Medicine today. While the toxic risk from mercury sulphide is relatively low, long-term use of this medicine may cause health problems. Mercury compounds are still found in some skin lightening creams, topical antiseptics, stimulant laxatives, nappy-rash ointmenteye drops, and nasal sprays. In the ingredients list, mercury can be hidden under the name ‘calomel’.

Dental uses

However, it is in the world of dentistry that the substance use is perhaps the most contentious. Amalgam fillings are about 50 per cent mercury, with the remainder a mixture of silver, tin, and copper. Advantages of amalgams include mercury’s inhibition of bacterial growth, and the fact that they are more durable than most other filling options. On the downside, amalgams are aesthetically unappealing, and can require the destruction of extra tooth structure, including healthy parts of the tooth, to fit them in. They also expand and contract with heat and cold at a different rate from teeth, which can cause cracking.

For the duration of the filling, mercury continues to enter the body in vapour form, generally as a result of chewing, brushing, and exposure to hot liquids. Levels are highest when the filling is being placed, or removed. Some people with amalgam fillings experience fairly marked health symptoms that can mimic those associated with MS.

Amalgams are slowly making an exit, being banned in Norway, Sweden, Denmark, and Russia. And restricted in Japan, Italy, Spain, Finland, Germany, and Austria. Here in Australia, they are still promoted as safe, but the percentage of fillings that are placed as amalgams has been shrinking over the years.

Among the benefits from seeing a holistic dentist, one is the absence of mercury vapour in the surgery, which often exceeds occupational safety levels. In one Scottish study, dentists were found to have urine mercury levels that were more than four times higher than control comparison subjects.

Amalgam removal

Many people who visit holistic dentists opt to replace their amalgam fillings, usually with composite materials. This procedure is not endorsed by the mainstream dental community, which sees it as unnecessary. But some patients report dramatic improvements in various health conditions after having their amalgams removed.

For safe amalgam removal, it is recommended to follow a protocol. The top priorities being using a rubber dam to prevent amalgam particles from being swallowed, and rinsing out the mouth before new fillings are placed. Afterwards, mercury is often removed from the body by taking chelating agents such as alpha lipoic acid, DMSA, and DMPS, often combined together. Fresh coriander leaf and garlic also have mercury chelating properties.

Dental mercury is finding its way into the environment. It is the largest source of mercury contaminating waste water and sewage sludge. Dentists can avoid contributing to this problem by using amalgam separators. Because these are expensive and not yet mandatory in Australia, not every dentist has one. So ask whether yours has one installed.

Crematoria emit, on average, ten kilograms of mercury a year from amalgam fillings.

Polluting the oceans

It is in the oceans that mercury from human activities is having the greatest effects. As smaller fish are eaten by predator fish, mercury and other contaminants are biomagnified up the food chain. Consequently, large predator fish such as tuna generally have higher concentrations than small fish such as sardines.

Food Standards Australia New Zealand recommends fish intake of up to two to three serves a week. They suggest greater restrictions on consumption of orange roughy (sea perch), catfish, shark, swordfish, broadbill and marlin. However, when visiting the fish counter, this advisory is nowhere to be found.

Mercury levels in the oceans, and in seafood, are increasing. A 2015 study looking at yellowfin tuna found that concentrations in the Pacific Ocean near Hawaii have been rising by 3.8 per cent a year. This is between 1998 and 2015.

Other tests by environment groups and NGOs show how this ocean pollution is translating into human exposure. The Japanese are keen fish-eaters, and hair samples from volunteers living in Tokyo were found with an average of 2.7 parts per million (ppm). This exceeds a hair mercury level of 1ppm associated with the US Environmental Protection Agency’s (EPA) expected safe intake dose in 95 per cent of cases. In the Cook Islands, insulated from industrial civilisation by thousands of kilometres of the Pacific Ocean, hair samples had an average of 3.3ppm, with 89 per cent exceeding the EPA level.

Curbing mercury pollution

Realising that the mercury problem was starting to get out of hand, in 2013 delegates from around the world signed what is known as the Minamata Convention, a UN mercury limitation treaty that was the culmination of three years of discussions. It has since been signed by 140 countries, including Australia.

It involves a phase-out of most non-essential uses of mercury (fluorescent lamps, soaps and cosmetics) by 2020. And it involves reducing usage or emissions (coal-fired power stations, industrial sources, and dental amalgam.)

NGOs and campaigners generally saw the agreement as being too weak, but a step in the right direction. Many aspects are voluntary, and there is no certainty that overall mercury emissions will be curbed. While those from existing coal-fired power stations are to be reduced, there is nothing in the agreement to prevent this gain from being eroded by the construction of new power plants. Our best hope is that they will be reined in by action on climate change.

Mercury-containing products are already banned in Norway and Sweden. They are subject to restrictive regulation in the EU and the US. In Australia, where there is an emphasis on non-binding voluntary action by industry, proactive individuals can help make a difference by steps such as avoiding dental amalgam and other products containing mercury, and responsibly recycling these items. Thy can also switch over to GreenPower, and install solar panels. They could even consider going off-grid.



Mercury Policy Project: www.mercurypolicy.org
Australians for Mercury Free Dentistry: www.mercuryfreedentistry.com.au
Recycling Near You: www.recyclingnearyou.com.au

About the author
Martin Oliver

Martin Oliver

Martin Oliver is based in Lismore, and writes on a range of environmental, health and social issues. He takes the view that sustainability is about personal involvement, whether this involves making our lives greener, lobbying for change at a political level, or setting up local eco-initiatives.

Share this post

Leave a Comment