Mercury: Myths And Facts

This section covers many of the common questions and myths surrounding the issues of mercury pollution and toxicity.

You may like to use the links below to navigate to the sections you are interested in.

General Mercury Myths

Myth: Mercury is a naturally occurring element - we shouldn’t be too concerned about any exposure.

Fact: It is true that mercury is found in the natural environment. Mercury comes in many forms - both organic and inorganic. Different mercury compounds have differing levels of toxicity - with organic forms like methylmercury being the worst.

Methylmercury is formed from inorganic mercury by the action of microbes found in the natural environment. This means that elemental and inorganic mercury when released into the environment is easily converted into methylmercury - which is extremely toxic. For this reason it is important to limit mercury exposure and mercury emissions wherever possible.

Myth: The dose makes the poison - small amounts of mercury do not really matter.

Fact: Dosage is just one of many factors for calculating toxicity, especially when it comes to neurotoxins with unusual properties like mercury. Individual factors like genetics, diet, health and age are all related to the body’s capacity to detox heavy metals like mercury.

Mercury bio-accumulates in the body over time, and for those with certain genetics becomes extremely difficult to remove any mercury at all. For these genetic types, the risk of harm dramatically increases over time as mercury concentrations in the body increases.

For women of childbearing age, or for those who are pregnant - this should be of concern. Unlike other metals, mercury is known to concentrate in the umbilical cord blood relative to maternal blood during pregnancy.

The World Health Organisation states "the inhalation of mercury vapour can produce harmful effects on the nervous, digestive and immune systems, lungs and kidneys, and may be fatal". Mercury exposure should be avoided through any means necessary.

Myth: It is easy to test your levels of mercury exposure.

Fact: Mercury has complex chemistry characteristics, which makes testing difficult. The truly accurate way to test for mercury exposure is a tissue sample - usually from fatty tissues like those found in the brain and kidneys where mercury concentrates. For obvious reasons this is impractical in a living person.

The next best option to test for mercury exposure is a combination of tests - hair (organic mercury), blood (organic mercury), urine ( inorganic mercury) and stool (both organic and inorganic mercury). Stool testing is the most accurate, easy way to test your levels of mercury exposure.

Myth: Recycling mercury waste is a good thing - it stops us mining more of it doesn’t it?

Fact: There are only two mercury mines left in the world and under The Minamata Convention they are to be shut down. The issue with mercury based products is not that we are heavily mining mercury - it is that through inefficiencies and poorly designed systems mercury is continually released back into the environment.

The lifecycle of mercury products, must be ended by directing mercury to long term storage where it cannot continue to pollute the environment and damage human health. The concept of recycling is to be commended for improving sustainability. However, toxic waste should NEVER be recycled unless the new product derived from the recycled toxin can be demonstrated to be safe and stable. This is definitely not the case with mercury.

Toxic waste that contains mercury such as dental amalgam, fluorescent bulbs, electrical and computer equipment and batteries can be collected as hazardous waste and sent to metal scrap recyclers. Melting the industrial waste and then distilling off the mercury recovers the inorganic/elemental mercury.

The recovered mercury waste is still toxic and is then sold usually to dental amalgam manufacturers and to artisanal small scale miners in developing countries. For this reason, many countries are legislating to ban the onsale of recycled mercury and directing the toxic waste to safe interim storage - ending the toxic lifecycle of mercury.

Mercury In Dentistry

Myth: Mercury in dental amalgam has been proven safe.

Fact:Even though dental amalgam contains 50% elemental mercury which makes it the highest concentration mercury added product, it is officially not classified as a poison because it has received a bureaucratic exemption from being included in the Poisons Standard by the Therapeutic Goods Administration.

Due to the very high mercury content, dental amalgam should be reclassified under Schedule 10 of the Poisons Standard "Substances of such danger to health as to warrant prohibition of sale, supply and use."

There has never been any studies conducted to prove the safety of mercury dental amalgam. This is because mercury dental amalgam been ‘grandfathered in’ as the product over 200 years old. Due to the age of mercury dental amalgam, it predates any safety testing required before a product can be used in health care services. If mercury dental amalgam was being brought to market today it would not be approved due to safety concerns.

The official position of the Australian Dental Association on the safety of dental amalgam can be found here - admitting that mercury vapour leaks from amalgam fillings. For a more thoroughly researched discussion of the safety dental amalgam - please refer to the Position Paper Against Dental Mercury Amalgam prepared by the International Academy of Oral Medicine & Toxicology available here.

Myth: Mercury in dental amalgam is bound to other elements and poses no risk to human health.

Fact: Despite claims from the dental industry, mercury is not stable in an amalgam filling. Mercury vapour is able to be measured in the saliva and breath of people with dental amalgam fillings.

Studies have also found mercury in umbilical cord blood of mothers with dental amalgams who have not eaten fish - suggesting that mercury readily leaks from the fillings and enters the bloodstream.

Mercury vapour is also visible under certain lighting conditions - please watch this video to see how much mercury vapour comes off an amalgam filling.

Myth: Mercury dental amalgam fillings are cheaper so they should still be available for developing nations and lower socio-economic demographics.

Fact: Economic studies that factor in the indirect costs of a mercury filling such as environmental clean up costs and health damages have determined that a dental amalgam filling costs an additional USD $67 per filling compared to a standard resin filling.

A mercury dental amalgam may be marginally cheaper for the patient, but on the whole to society they are far more expensive due to environmental and health damages. It is fiscally irresponsible to suggest the continued use of a product like mercury dental amalgam that has well documented negative financial impact on the taxpayer.

Myth: No suitable substitutes exist for dental amalgam.

Fact: Substitutes for dental amalgam have been available for about 60 years. Resin fillings do not require as much tooth structure to be removed and do not expand and contract like amalgam every time you eat something hot or cold. These dimensional changes of the amalgam fillings causes stress fractures within the tooth leading to cracks and unnecessary tooth structural loss.

The ideal filling should match natural properties of the tooth like resin, and unlike amalgam which required more repeated dental intervention over time. It is possible for a dentist to rebond onto a resin filling, while they cannot repair an amalgam filling - needing to replace the whole thing.

It should be noted that if you are replacing an amalgam, choose a dentist who prioritises bio-compatibility and does not use resin fillings with chemicals like BPA. You may like to start by finding a SMART certified dentist here.

Myth: Dental amalgam fillings are stronger and therefore are better options than resin fillings.

Fact: When considering a material to fill a tooth it is clear that the strength of a metal is unnecessary. The ideal material should mimic the natural properties of a tooth.

Because a mercury dental amalgam filling is metal, it swells and shrinks within the tooth in response to temperature changes. Over time this swelling cracks the tooth - causing further dental complications. A resin filling does not respond like an amalgam under temperature changes, so will be a better choice for retaining the integrity of the tooth’s natural structure long term.

Myth: The dental industry in Australia doesn’t even use mercury fillings anymore.

Fact: The Australian dental industry has been rebranding mercury amalgam fillings as ‘alloys’ and ‘metallic’ fillings. Mercury dental amalgam is frequently misconstrued as a ‘silver’ filling noting the appearance not the actual chemical composition.

Unfortunately many dentists using amalgam follow deceptive practices - when patients ask for the composition of the amalgam filling the dentist will only state the composition of the metal powder, not the liquid mercury that is mixed with the powder to form the amalgam.

The exact use of mercury fillings in Australia is unknown as there have never been any quantitative studies conducted on this topic. However, UNEP estimates that global usage remains unchanged over the last 10 years. This is concerning as most industries that use mercury based products (such as batteries and lighting) are seeing those products decline. Dentistry unfortunately continues to use mercury at a similar rate to historical levels - public education and government intervention are needed to reduce the use of this harmful product. If mercury dental practices are not curtailed there could easily be more dental amalgam being used during periods of population growth with increased dental decay rates.

Myth: Dental amalgam fillings are safe for dental staff to prepare and use.

Fact: Studies show that there are significant levels of mercury released into the air during the preparation, placement, repair and removal of an amalgam filling - regularly exposing dental staff to levels of mercury well outside Occupational Health & Safety limits.

In a predominately female workforce - this mercury exposure increases the risk of miscarriage, birth defects and host of other health issues.

Autopsy studies have confirmed the risk, showing very high levels of mercury in the brain for dental workers. This is supporting evidence to the theory that dentists have far higher suicide rates than most professionals because of their high levels of mercury toxicity.

Myth: The Australian Dental Association says mercury amalgam fillings are safe - they know best right?

Fact: Organisations like the ADA are not a scientific body - they are a professional industry group. Organisations like these have vested interests in maintaining the status-quo - which is deregulation for mercury products like dental amalgam. The ADA does indirectly admit that mercury from dental origins is a problem for humans and the environment, which is why they have policies on reducing dental sector waste.

For organisations like the ADA to admit that dental amalgam causes direct harm could potentially open up legal liability issues for dental amalgam manufacturers, and could also be a huge blow to the ADA's public credibility. Since 1998, the National Health and Medical Research Council (NHMRC) has recognised the health risks of mercury dental amalgams, stating that the product should not be used in children, women of childbearing age or those with renal issues.

Many countries internationally have already recognised the harm, and banned dental amalgam - it is time for Australia to step up and follow suit.

Myth: Most dentists have systems in place to stop mercury entering into the environment.

Fact: Unfortunately this is not true - most dental clinics are not equipped to handle mercury waste and prevent it from entering the environment. Once mercury has been removed from a tooth it is considered toxic waste by the government and must be collected by a registered collection agency. This collection is only required for removed particulate matter, ignoring mercury waste entering the air and water.

In Victoria, the ADAVB started the Dentists For Cleaner Water Program where about 70% of private dental clinics collected amalgam waste with separator machines. Public dental clinics in Victoria now also use separators machines. This is a good start and extending initiatives like this nationally across the public and private sectors is important. Countries like New Zealand and Canada already have legal regulations in place requiring separators in dental clinics.

For a dentist to be SMART certified - they must have amalgam separators installed, and also use air filters to collect airborne mercury particulate (about 70% of mercury goes into the air).

The ADA position statement on environmental waste from mercury amalgam is available here


Choose a SMART certified dentist for having any mercury amalgam fillings removed - you can find one here.

Mercury In The Food Chain

Myth: A little bit of mercury in my fish or seafood isn’t really a problem.

Fact: Mercury is toxic and bioaccumulative. This means that eating a little bit of fish frequently could develop high levels later on in life. As we age, our enzymatic processes become depleted and this impairs our capacity to have optimal performance of detoxification pathways. It is important to have periodic assessment of mercury levels and if elevated then appropriate detoxification should be undertaken.

It is hard to know exactly how much methylmercury is in each piece as the fish or seafood is not being tested regularly prior to going to market and purchased for consumption by the consumer. We hope that in future, testing kits for this purpose will be developed to protect the unsuspecting consumer.

Another consideration is that certain people are allergic to mercury and may not know this. People who react to metals only need a trace exposure to damage their immune system. Based on statistics from the North American Contact Dermatitis Group, it is estimated that approximately 21 million Americans are allergic to mercury. However, this figure could be even higher because recent studies and reports tend to agree that metal allergies are on the rise.

Myth: The benefits of the protein, selenium and omega 3 acids in fish outweigh any damage caused by mercury.

Fact: Fish is an important source of animal proteins and other nutrients. Fish and shellfish are low in saturated fats, and they provide antioxidants such as selenium and vitamin E. They also offer beneficial omega-3 polyunsaturated fatty acids, which are important for optimal development of motor skills, the brain and vision and protection against cardiovascular disease.

Because fish have naturally high levels of selenium, this offers them some protection against mercury exposure. Since the dawn of time, natural mercury emissions have been coming from volcanoes and from within the ocean bed. Adaption of the ocean creatures to show tolerance to mercury levels is to be expected. However in modern times the extent of toxic pollution has never been seen before - the inherent antioxidants, fatty acids and selenium are no longer adequate to provide the protection needed to combat the poison in our oceans.

Studies have demonstrated that supplementing with selenium and vitamin E do not decrease mercury levels in tissues of animals given methylmercury. Although, the animals with supplementation were able to accumulate high levels of mercury without showing signs of toxicity compared to the animals that were not receiving supplements.

Whilst it is commonly known that mercury is a potent neurotoxin, equal attention should be given to the fact that mercury is a potent cardiotoxin. Mercury is considered an important risk factor for cardiovascular disease that could play a role in the development of cardiovascular events. The association between mercury exposure and an increased risk of developing cardiovascular and neurological diseases is apparent. In the cardiovascular system, mercury increases the production of free radicals and induces hypertension in humans and animals.

Given this information, a logical approach would be to keep dietary mercury sources to the minimum and to supplement with the antioxidants for optimal protection.

Myth: If I stop eating fish, I'll be protected from mercury poisoning.

Fact: Mercury is a poisonous, persistent, omnipresent pollutant. Many new pathways of mercury entering into the food chain have been identified. In Iraq, mercury poisoning occurred in 1971 when wheat grains were treated with fungicides containing organic mercury. This poisoning killed over 500 people who ate bread made with contaminated wheat.

Mercury based fungicides are commonly used on sugar cane crops in Australia along coastal Queensland and northern NSW. This not only pollutes the surrounding Great Barrier Reef Marine Park, but there is concern of mercury residue contaminating soil and food products.

Mercury levels are increasing in plant life due to the precipitation and deposition of mercury emissions. Mercury contaminated fertilizers derived from human biosolids is being used in agricultural processes. The source of this mercury is primarily derived from people who have dental amalgam fillings and from the discharge of dental clinics that have not installed separator devices.

Some livestock have also been tested to assess mercury levels due to concern about the practice of being fed fishmeal which contains methylmercury. The findings were concerning - suggesting that this may be contributing to mercury exposure from eating common meats like poultry, pork and beef.

To summarise - if you are concerned about mercury impacting your health, the two easiest things to do are to reduce high risk seafood consumption and safely remove any dental amalgam fillings. However, be mindful that there are many other sources of mercury exposure and make conscious efforts to avoid them.

Myth: Organic mercury must be less harmful than the other types of mercury.

Fact: It can be confusing reading about the different types of mercury that people are commonly exposed to like - inorganic, metallic, elemental, methylmercury, organic mercury and mercury vapour. All forms or “species” of mercury are regarded as toxic.

It is commonly understood that “organic” foods are supposedly healthier due to the absence of intentional chemical treatments. However, when describing the various species/forms of mercury it is quite the opposite. Organic mercury is the same as methylmercury and is very dangerous.

Methylmercury is made by the certain types of microorganisms found within the environment and within human and animal's digestive tracts. These microorganisms convert the inorganic mercury using biological processes. Strangely, these microorganisms seem to be resistant to the byproduct of methylmercury that they produce.

To clarify any confusion, inorganic mercury is the same as elemental and metallic mercury and this is the type of mercury found in dental amalgam and fluorescent bulbs. Inorganic mercury can be converted into the most dangerous form - methylmercury by microorganisms.

Mercury From Power Generation

Myth: Australian coal has much lower levels of mercury than the USA, so we don’t need regulations on coal power plant emissions.

Fact: We have seen some positive steps towards reducing pollution and also carbon emissions through the closure of some of Australia’s worst polluting power plants like Hazelwood.

The Marsden Jacob Report commissioned by the Australian government looks at the cost benefit analysis of ratifying the Minamata Convention. Regarding coal power plants - the report concluded that an additional $224 million would be required for a new coal power plant to meet the best environmental practises. These costs for clean air, and a clean environment is likely to have a significant impact on the price competitiveness of coal power generation - suggesting that resources would be better invested into clean, renewable energy rather than new coal powered plants.

Myth: The Australian Government already has regulations in place to protect air quality from industry activity.

Fact: In 1998, the National Environment Protection Council (NEPC) made Australia's first national ambient air quality standards - looking at 6 pollutants: carbon monoxide, nitrogen dioxide, ozone, sulphur dioxide and lead.

This ambient air quality standards are narrow - and are not nationally binding air quality emissions standards. This means industry is not required to measure or regulate their output of pollutants and toxins.

Well known, toxic pollutants like mercury currently are not regulated under emission standard legislation by the federal government.

Myth: There is only a small amount of mercury that comes from coal power - it isn’t a problem.

Fact: The 2013 report from the United Nations Environmental Programme found that coal burning emissions for power generation and industry account for about a quarter of global mercury emissions.

Coal itself is not particularly high in mercury, however the scale of coal burning for power generation is massive - creating huge amounts of mercury pollution and also significantly contributing to climate change.

Myth: Most mercury emissions in the air come from natural sources like volcanoes - coal power isn’t the main issue.

Fact: The United Nations Environmental Programme report from 2013 found that only about 10% of mercury emissions are from natural geological processes - like volcanoes.

In 2010, coal power accounted for about a quarter of anthropological mercury emissions, with about 474,000 kg of mercury being dumped into the environment through the burning of coal.

Disturbingly the UNEP predicts that by 2050 there are likely to be substantially higher mercury emissions than today due to growth of Asian economies like China and India. Major technological shifts are needed in power generation to reverse the mercury pollution trend.

Myth: There would be no measurable benefit of reducing mercury pollution from coal power plants.

Fact: Impairment of IQ has been clearly linked to mercury exposure, especially affecting the developing brains of children. Most studies use IQ levels for cost benefit analyses when examining the potential benefits of regulating toxins like mercury and lead.

The Marsden Jacob report found that mercury exposure at mean levels would lead to a loss of 36 IQ points, and at maximum levels a loss of 191 IQ points. The report estimates a loss of economic productivity of AUD$30,030 per IQ point lost.

Not only is there a moral argument for protecting the health of children, there is an economic argument - to ensure healthy, happy and productive children as the future of Australia’s economy.

Myth: Halogen Bulbs are better than Fluorescent Bulbs because they don't have any mercury.

Fact: Whilst this is technically true, Halogen Bulbs are very energy inefficient. To compare, Halogens use about five times more energy than Fluorescent bulbs - this means that more coal is going to be burnt to generate the additional power required by Halogens.

For the best energy efficiency and the lowest mercury emissions - transition to LED lighting powered by renewable sources.