Mercury (Hg) in Drinking Water

A technical paper by Olympian Water Testing specialists

Mercury in Drinking Water

Mercury is a naturally occurring dense, silver-white metallic element in the environment, which is liquid at normal pressures and temperatures [1]. Mercury is widely distributed through natural processes, including volcanic activities and rainwater [2]. Low levels of Mercury are also found in water and food substances and are harmless to the body. Mercury is mainly found in manufactured devices, including switches, dry-cell batteries, barometers, thermometers, and fluorescent light bulbs. It is also found in natural ore deposits worldwide [2]. The two kinds of Mercury are organic and inorganic Mercury. Inorganic Mercury has more detrimental effects on a person’s health than organic Mercury [3]. We aim to educate you about Mercury contamination of water, its effect on your health, what you can do mitigate them and how to decontaminate water.

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[2] “Lead Poisoning.” Centers for Disease Control and Prevention.
[3] “A Brief History of Lead Poisoning.” Environmental Defense Fund.
[4] “Flame Tests.” Chemguide. https://www.chemguide.co.uk/

How does Mercury contaminate drinking water?

Volcanoes and the weathering of rocks

According to geologists, volcanoes are the largest sources of Mercury in the global atmosphere. Volcanic eruptions emit mercury gas into the atmosphere, where it circulates before raining and flows back on the earth’s face. In addition to volcanoes, fumaroles, solfataras, and geological anomalies also contribute to Mercury released in the atmosphere [4]. Weathering rocks release elements of Mercury that seep into groundwater, contaminating nearby rivers, lakes, and wells [5]. The United States Geological Survey showed that the primary mercury source in the environment was human activity, including the electricity, coal, and waste disposal industries [6].

Rain and snow

In the US, rain and snow are the primary sources of aquatic bodies as Mercury falls back to earth from the atmosphere with rain. Rainwater has an equivalent of 5–100 ng/liter levels of mercury [2]. Mercury can be deposited into water bodies such as rivers, water wells, and lakes when it rains or snows. Moreover, some water bodies may receive Mercury directly discharged from industries [5, 6].

Metal Production and mining

Mining wastes are also potential sources of Mercury. For example, when mining gold, the miners use chemicals containing Mercury. Elemental Mercury is utilized to extract gold from ore in the form of amalgam, separated by hand, and then it is heated to separate the gold and evaporate the Mercury. It is estimated that more than 1000 tons of Mercury are released every year from small-scale gold mining’s tailings and vaporized Mercury [7]. Releases from chemical spills and past mining or improper disposal of mercury-containing chemicals may also get into the water.

Emissions from coal-fired power plants

The US Environmental Protection Agency (USEPA) states that coal-fired power plants’ emissions are the largest sources of Mercury emitted into the atmosphere in the United States (US) [8].

[1] “Lead and Copper Rule: Sampling for Lead and Copper in Drinking Water.” U.S. Environmental Protection Agency.
[2] “Soil Sampling and Analysis.” University of Kentucky College of Agriculture, Food, and Environment.
[3] “Lead in Air.” U.S. Environmental Protection Agency.
[4] “Lead Poisoning.” Centers for Disease Control and Prevention.

Health Effects of Mercury

Mercury from the atmosphere is inorganic Mercury, and once Mercury has been released into the environment, it can be changed by microorganisms in soil and aquatic environments into the physiologically harmful form of methylmercury (MeHg) [6].

Mercury has adverse health effects on human health, hence the need to test your drinking water. It harms the nervous, immune, and digestive systems, eyes, skin, lungs, and kidneys.

Possible symptoms of mercury poisoning, mostly neurological, include [9]:

Muscle weakness
Impaired vision, hearing, and speech
Impairing sensation
Lack of coordination of movements
Impairment of speech, hearing, walking; and
“Pins and needles” feelings in the feet, hands, and around the mouth.
Tremors
Memory loss
Insomnia
Lethargy

Mercury is a neurotoxin, and any exposure can be subtle, severe, or fatal if large quantities are consumers. The effects of Mercury in the body depend on multiple factors but are not limited to:

The type of mercury contaminant found in the water.
The quantity of mercury contaminant
The age of the person (children tend to be more vulnerable than adults)
The duration of exposure (days, weeks, months, years, or decades) and how the person was exposed.
The route of exposure (injecting, touching, eating, breathing)
Whether the exposed person has preexisting conditions or illness

Unborn infants and children are more affected by mercury-contaminated water, especially when exposed to organic and inorganic forms of Mercury. Any exposure can result in memory loss, brain damage, impaired vision, irritability, and hearing dysfunction. Additionally, research has shown that babies born to mothers who had consumed methylmercury were more likely to have cerebral palsy and developmental abnormalities [3]. Thus, Children exposed to methylmercury are more likely to exhibit impaired visual-spatial skills, memory and cognitive abilities, fine motor skills, attention, and language.

Cancer

According to EPA, there is limited data that exposure to Mercury causes cancer. However, evidence suggests that exposure to high levels of Mercury can increase different types of tumors in mice and rats. Research involving rats exposed to high mercury dosage developed thyroid or stomach cancer [10]. The USEPA classifies mercuric chloride, an inorganic mercury salt, and methylmercury, an organic mercury, as possible human carcinogens. However, studies have indicated that mercury toxins induce oxidative DNA modifications and inhibit DNA repair, increasing risks for malignancy [11, 12].

[1] “Analytical Techniques for Lead Analysis.” International Lead Association.
[2] “Lead Analysis.” Sigma-Aldrich.
[3] “Biological Detection of Lead.” U.S. Environmental Protection Agency.

Why should I test My Water for Mercury contamination?

Water is a critical resource essential for the human body and life. The purity and clarity of drinking water should not be taken for granted because any impurities can cause adverse health effects.

The Agency for Toxic Substances and Disease Registry (ATSDR) states that less than 0.01% of Mercury is absorbed into the body after consuming contaminated water [10]. Therefore, amounts more than ATSDR’s standards are adverse to the body.

The USEPA states that the minimal levels of Mercury contamination should be 2 ppb (parts per billion) of divalent Mercury [13]. Quantities above 2 ppb or above 100 ng/mL are linked with Mercury poisoning.

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[7] “Analyzing Elements: Selection of Analysts.” Sigma-Aldrich.
[8] “Guidelines for Drinking-water Quality.” World Health Organization.

Is regular water testing for mercury contaminants necessary?

Water should be tested regularly for mercury contaminants and other impurities that can harm human health. If you suspect your drinking water is contaminated, consult a professional for mercury testing services. Mercury is odorless and can reach hazardous levels and increase the chances of chronic exposure without notice. Water testing is necessary, given that a Consumer Confidence Report should be offered annually for most water systems as required by EPA [14], and water contamination can happen at any time in the year.

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[4] “Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Atomic Fluorescence Spectrometry (AFS).” Sigma-Aldrich.
[5] “Lead Analysis Using Inductively Coupled Plasma Mass Spectrometry (ICP-MS).” U.S. Environmental Protection Agency.

Mercury Removal from Drinking Water

Four main processes effectively remove Mercury from water: reverse osmosis, granular activated carbon (GAC), coagulation (filtration), and lime softening. Boiling your drinking water is not recommended for a mercury removal treatment [15]. There is also the option of choosing an alternative water source if the one you use has traces of Mercury. However, the most effective method is to treat your water to eliminate mercury contaminations.

Reverse Osmosis

Reverse Osmosis water filter forces tap water through a membrane where larger ions are blocked from passing through. This water filtration system has filters of composite membranes containing Kinetic Degradation Fluxion (KDF) media to reduce mercury levels in your drinking water [16]. Ensure suitable filters and cartridges are installed as part of the Mercury purification. Reverse osmosis is the most economical technique that removes 90% to 99% of all the primary contaminants [17]. The reverse osmosis membranes’ pore structures are tighter for producing high-quality water. However, you will need higher efficiency systems if you filter high volumes of water.

Distillation

The water distillation systems remove all the primary solid contaminants, such as Mercury and Lead, through boiling and condensation. Water distillation systems come in different shapes, and you can purchase a smaller one to purify your drinking water.

The main challenge is that smaller distillation systems only produce small water amounts. A distillation system is more expensive than reverse osmosis because you first need to use power to boil water.

Granulated Activation Charcoal (GAC)

Granulated activated carbon (GAC) filters are another method for removing Mercury from water. GAC filters are simple, inexpensive, easy to use, and depend on a porous carbon medium, such as a heavy charcoal material used to remove mercury components [18, 19]. When the water passes through the GAC medium, the Mercury and other dissolved contaminants get trapped on the activated charcoal surface [18]. However, the GAC has some limitations that can affect its effectiveness. The GAC filters rely on the mercury concentration in water and the water’s pH sensitivity, and GAC filters should periodically be replaced for maximum performance. Nonetheless, GAC is an effective method for water pH close to 7. Furthermore, the GAC filters should periodically be replaced for maximum performance.

Lime Softening

Lime softening entails the utilization of excess limewater or calcium hydroxide to increase water pH levels to precipitate out the heavy metal contaminants such as Mercury as Mercury Hydroxide [20]. Besides removing Mercury, this method also helps soften water by removing water hardness. For example, lime softening effectively removes magnesium and calcium precipitates from drinking water. Lime softening is recommendable because it is a reliable and cost-effective mercury removal method.

Filtration

Aluminum sulfate (AISO4) solution is used for the water treatment process. AISO4 reacts with the Mercury and helps remove it from the contaminated water through precipitation or coagulation [21, 22]. After the process is completed, a sludge is formed that should be safely discarded afterward.

[1] “Inductively Coupled Plasma Mass Spectrometry (ICP-MS).” Sigma-Aldrich.
[2] “Atomic Absorption Spectrometry (AAS) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES).” Sigma-Aldrich.
[3] “Lead Analysis Using Inductively Coupled Plasma Mass Spectrometry (ICP-MS).” U.S. Environmental Protection Agency.
[4] “Analyzing Elements: Data Reduction and Statistical Analysis.” Sigma-Aldrich.

Factors to consider before selecting a Mercury treatment method

Water quality

Before installing a water purifier, first, know the quality of the water. Testing water quality helps determine the type of purifier needed and the contamination to remove.

Ease of installation

Always select a purifier that is easy to install and operate. For example, under-the-counter water purifiers are easy to install because they dispense water through the tap. Additionally, they do not require power because the purification process is initiated as water pushes through them.

Maintenance Needs

The proper functioning of the purifier depends on maintenance, which includes changing the filters. The filters must be replaced regularly, especially when the alarm goes off. An under-the-counter water purifier is cost-effective and requires less maintenance.

Space for Tap

The kitchen top is where you fix a tap for the purifier and should therefore have a hole. If the kitchen top lacks an open space for fixing the tap, have a professional drill for you and use it when fixing the tap of the water purifier.

Also, ensure the place you will install the water purifier is clean and dirt-free. The sink should not have a leakage, especially where you place the water purifier.

Budget

The most crucial factor to consider when purchasing a purifier is your budget. The budget should include the operational and maintenance costs, the initial cost of buying the system, and filter change costs. Choose wisely and purchase a purifier that best suits your financial budget and water filtration requirements.

Water Pressure and Flow rate

The flow rate of water pressure should be checked before completing the water filtration system installation process. Each water filter system comes with a different range of pressure. Select the best and most efficient purifier to save time and operation costs.

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[9] “Validation in Analytical Chemistry.” Royal Society of Chemistry. https://www.rsc.org/

Does boiling water remove Mercury?

Boiling water to remove Mercury is a misconception held by the majority of people. The goal of boiling water is to remove bacteria and solid wastes, not hard metals, including lead and Mercury. It is not recommendable to boil water because such a process can increase inorganic mercury levels in the water. Water boiling point is 100 degrees Celsius maximum, below most metals’ boiling point, including mercury (356.7 degrees Celsius). Therefore, Mercury can be removed by boiling water.

Please consider water treatment methods such as GAC filters and reverse osmosis, professionally designed to remove Mercury.

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[2] “Lead: TSCA Regulations.” U.S. Environmental Protection Agency.
[3] “Federal Laws Regulating Lead.” U.S. Environmental Protection Agency.
[4] “ISO/IEC 17025:2017 – General requirements for the competence of testing and calibration laboratories.” International Organization for Standardization.
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[6] “National Environmental Laboratory Accreditation Program (NELAP).” U.S. Environmental Protection Agency.
[7] “Accreditation Bodies Recognized by the EPA.” U.S. Environmental Protection Agency. https://www.epa.gov/

Why You Need a Water Purifier to Remove Mercury

Mercury is a harmful element when consumed, and it is present in large amounts in the US water bodies, such as Lake Michigan, the leading water supplier of drinking water in Chicago. A water purifier is needed to protect your health and those you care about. A reverse osmosis water purifier can help remove heavy materials such as lead, Mercury, and other volatile organic metals, fluoride, and arsenic compounds, highlighting its multiple advantages.

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Mercury - Frequently Asked Questions

What is Mercury?

Mercury is a heavy, silvery-white metal element that exists as a solid crystal or a liquid at room temperature [23]. Liquid mercury is odorless, invisible, and produces toxic vapors. Mercury is found in electronic devices, skin products, drinking and lake water, and fish.

Do industrial wastes contain Mercury?

Industries are the number one pollution contributor because their waste products may contain large amounts of Mercury. Electrical products such as fluorescent light bulbs, dry-cell batteries, and other equipment account for 50% of Mercury [6].

How much is Mercury released to the environment?

The natural process releases large deposits of Mercury from the earth’s crust. Combustion of metals, fossil fuels, municipal landfills, sewerage, and metal refining operations are essential sources of Mercury.

Should I be worried about eating other things containing Mercury besides drinking water?

Yes. Fish may have Mercury if they are from a contaminated river or lake.

Will exposure to Mercury result in harmful health effects?

Drinking water with Mercury or eating contaminated food exposes your body to several health effects. The following are examples of health effects you may experience after exposure to high mercury levels.

Confusion, hand tremors
Chills
Chest tightness, bronchitis, pneumonia
Abdominal pain, nausea, vomiting, and loss of appetite
Bleeding gums
Leg pains and burning sensation in feet
Lung and kidney damage
Skin rashes.
Reproductive effects include menstrual problems

What are the standard regulatory levels of Mercury in drinking water?

The federal and state drinking water standards are 2 parts per billion (ppb) of Mercury. Stop drinking and using that water with more than 2 ppb of Mercury for domestic purposes. For higher levels of Mercury, avoid bathing, washing, or other purposes, including farming.

Can I remove Mercury from drinking water?

It is possible to remove traces of Mercury from drinking water. First, you need to contact professionals to perform testing and analysis of your water in order to learn about any mercury contamination levels. The commonly used mercury removal practices include reverse osmosis, GAC filters, lime softening, distillation, and special cartridges and filters.

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