14 Nov 2019 Story Chemicals & waste

Many products still contain mercury. These alternatives could replace them

Photo by UN Environment Programme/ Veejay Villafranca

Mercury—a toxic heavy metal that can cause serious and lasting health problems—turns up in many places that you wouldn’t expect. It has now been more than two years since the entry into force of the Minamata Convention, a global treaty to protect human health and the environment from the adverse effects of mercury. But the production of many mercury-containing products continues around the globe.

“Mercury is to be managed using a circular approach, that aims at protecting human health and the environment from the negative effects of mercury and mercury compounds, says Rossana Silva Repetto, Executive Secretary of the Minamata Convention.

The good news is that a wide range of safe and high-functioning alternatives to mercury-containing products have been developed. And thanks to the Minamata Convention—specifically Article 4, which requires that countries take measures to phase out the production and trade of mercury-containing products, and Annex A, which sets out deadlines for that process—it’s just a matter of time before mercury-free alternatives fully replace their more toxic counterparts. Ahead of the third Conference of the Parties to the Minamata Convention, which will gather in Geneva from 25–29 November, we’ve compiled a list of some of the most useful innovations that are 100 per cent mercury-free.

Dental amalgam

If your dentist has ever told you that you have a cavity and you’re over a certain age, then there’s a good chance that you’re walking around with a small amount of mercury in your mouth. Dental amalgam, which is used to fill the cavities in teeth, is traditionally made up of a mix of mercury and a metal alloy that contains silver, tin and copper. Scientists have developed a number of mercury-free alternatives for fillings, but these tend to be more expensive than traditional amalgam and are not so widely used. Alternatives include composite fillings, which can be made of powdered glass quartz, silica or other ceramic particles added to a resin base; glass ionomer fillings, which form a chemical link with the tooth; and porcelain or gold inlays, which are very long lasting but relatively expensive. Other approaches—including laser, ultrasound and drug-based treatments to stimulate the regeneration of dentine—are also being developed.

Batteries

Kitchen scales. Watches. Laser pointers. Pocket calculators. Kids’ shoes that light up when they walk. What do these products have in common? They all can require button cell batteries, which usually contain very small amounts of mercury. That mercury poses no threat to the environment or human health if the batteries are used and recycled appropriately, but if the batteries end up in an incinerator or in an inappropriate landfill, then the mercury inside them can leak out and contaminate the air or groundwater. Another type of mercury-containing batteries—mercuric oxide batteries, which can provide a stable current over a long lifespan—are still used in hospitals and in some military and commercial applications around the globe. However, scientists have developed a range of mercury-free battery alternatives, including lithium, silver and alkaline batteries, which can perform just as well as their mercury-containing counterparts, although they may come with their own, separate environmental challenges. These products are often more expensive than traditional batteries, but their prices are falling as the technologies develop.

Jewelry

Do you wear gold jewelry? If so, it’s possible that whoever mined the metal that ended up in your ring, earrings or necklace used mercury to separate the gold from the surrounding material. In fact, artisanal and small-scale gold mining represents the single largest demand for mercury worldwide; it’s also the most important contributor of combined mercury emissions into air and water. So whenever you’re buying jewelry, make sure to ask your retailer for products made from certified and sustainable gold. 

Coal burning

The burning of coal is the single biggest source of human-induced mercury emissions into the Earth’s atmosphere. Coal burning for power generation has traditionally increased alongside economic growth, and so too have its mercury emissions, which have more than tripled since 1970. While many people have may have no direct control over where their electricity comes from, they do have the power to choose what they burn to cook and heat their homes. Indeed, household coal burning is also a significant source of mercury emissions and a human health hazard. At home, you can choose to burn wood instead of coal. You can also call on your electricity provider to switch to cleaner sources of energy, or at least to take steps to reduce its mercury emissions. Indeed, power plants can slash their mercury emissions by as much as 95 per cent of by improving coal and plant performance, and optimizing control systems for other pollutants.

Fluorescent lamps

Fluorescent lamps produce usable light much more efficiently than incandescent light bulbs, and thus can be very useful for reducing the overall energy consumption of a home or business. Compact fluorescent lamps are growing in popularity, largely for this reason. However, all fluorescent lamps contain mercury, and thus they must be handled—and recycled—with care. Light-emitting diode (LED) bulbs, which are also energy efficient, are a popular alternative to fluorescent lighting, and LEDs contain no mercury. Another efficient and mercury-free lighting alternative is the electron-stimulated luminescence bulb, which uses accelerated electrons to stimulate phosphor to create light.

Paint

Mercury was for a long time a key ingredient in latex paints and other types of paint, with negative impacts on human health. In 1989, a four-year-old boy in Michigan in the United States was hospitalized for several months with mercury poisoning after breathing paint fumes in his newly painted house. The following year, the United States banned the use of mercury in interior latex paint. A review published by the European Union in 2008 found that mercury could still be detected in paints being produced in Europe. Plenty of affordable and effective alternatives exist, however, and these are now widely available worldwide. Be sure to check the label on your paint, and always choose a reliable supplier.

Thermometers

Traditional mercury thermometers were invented in the 18th century by Fahrenheit himself (Daniel Gabriel Fahrenheit, that is—a Dutch physicist). His invention was used in close to its original form for more than 200 years, but following World War II scientists developed alternatives that are mercury-free. Today, digital thermometers are widely available, although their button cell batteries may contain small amounts of mercury, so it is important to recycle the thermometers appropriately after the batteries die. It’s also possible to find liquid-in-glass thermometers that contain a non-mercury substance that isn’t toxic when swallowed or inhaled; these thermometers should be labeled “mercury-free.”  

Blood pressure meters

It’s incredibly important for medical professionals to be able to get a precise blood pressure reading, but traditionally the best way to do so was to use a device that contains mercury, the mercury sphygmomanometer. And while these devices are still very common in hospitals and doctor’s offices around the world, mercury-free alternatives have been developed—and have proven to be just as accurate and effective as their mercury-containing counterparts. In the United States, the Center for Disease Control and Prevention has recommended that mercury sphygmomanometers be replaced by digital devices or other mercury-free alternatives. The European Union has noted that, while the traditional devices are gradually disappearing from use, some should be kept as reference standard for validating new methods of measurement.

By opting for mercury-free alternatives, you can help to protect people and planet from the toxic effects of mercury. Taken together, our individual actions can have a monumental global impact.

 

Want to learn more? Visit the website of the Minamata Convention, check out the 2018 Global Mercury Assessment, and get all the details on the upcoming Conference of the Parties.