We now have a better understanding of the risks associated with mercury – a heavy metal used extensively during the 20th century that can still be found in thermometers, cosmetics, pesticides and more.
Mercury exposure harms the immune system, brain, heart and lungs, sometimes leading to permanent memory loss and language impairment. Even very low levels can cause irreversible damage to humans, animals and flora.
Phasing out the use of mercury is widely supported by governments around the world, and a framework for doing so, the Minamata Convention, was drafted a decade ago.
Now, after much delay, the Australian Government is expected to ratify the convention. Importantly, 90 days after ratification (likely to be March 2022), it’s likely the import, export and manufacture of certain products containing mercury will be prohibited.
Lighting the way
The implications for councils are significant because an estimated 20 per cent to 35 per cent of Australia’s 2.5 million street lights still use high-pressure mercury vapour (HPMV) lamps. (The new rules mean imported replacement lamps will no longer be available.) HPMV lamps typically last for up to four years, which effectively means councils have four years at most to replace any street lighting that uses them.
“Mercury vapour lighting was, until recently, the dominant type of public lighting in Australia,” explains Graham Mawer, director of lighting consultancy Next Energy. “A decade ago, more than half of our public lighting used mercury vapour lamps.”
The technology was commercialised in the 1930s, when the dangers of mercury were not well understood. Because the lamps were cost-effective, they quickly became ubiquitous.
Towards the end of the 20th century, calls to phase out the use of toxic mercury grew louder. At the same time, LED lighting technology was becoming more powerful and less expensive.
By 2013, when Australia signed (but did not ratify) the Minamata Convention, many jurisdictions around the world had already begun swapping their mercury vapour lighting for LEDs. Although mercury vapour lamps were no longer manufactured in Australia, importing them remained relatively cheap.
But this is set to change when the convention is ratified and imports are banned. “It will become like having a car but not being allowed to buy petrol,” says Mawer. “Once the current tank runs out, you’re done.”
As many as 800,000 street lights in Australia will become obsolete if the new law is ratified, as expected. While councils may wince at the thought of replacing their existing street lights with LEDs, Mawer explains the new technology is substantially cheaper to operate over the long term.
“Modern LED luminaires use between 50 and 80 per cent less energy than mercury vapour luminaires and operate much more reliably,” he says.
For example, he says, councils in residential Sydney are achieving the same lighting outcomes with LED street lights as they were previously, but are using 80 per cent less energy. “What we used to do with an 80-watt mercury lamp is now being achieved with a 17-watt LED,” Mawer says.
And the technology is only improving as it proliferates. That means councils can look forward to even greater cost savings.
LEDs have other benefits too. For example, they don’t generate heat and therefore don’t contribute to the urban heat-island effect. The myth that LED lighting can easily damage your eyes is fast fading from public consciousness.
“LED lighting is the future, and the future is here,” says Mawer. “It’s a no-brainer.”
Mercury’s long shadow
Although the Minamata Convention is still subject to a final decision from the Australian Government, 135 other countries have already ratified it. As a result, far fewer products containing mercury are being manufactured internationally, and mercury vapour lamps are becoming more difficult to source.
However, Australian dentists still use dental amalgam, which contains mercury, for tooth fillings. Dental amalgam must be phased out by signatories to the convention, but there is no deadline.
Other products containing mercury, such as old thermometers, still circulate in Australia, too.
The risks associated with mercury have been known since the 1950s, when thousands of Japanese people living in coastal Minamata were poisoned by industrial waste water tainted with the metal.
Until recently, there weren’t good alternatives to mercury for certain applications. Today, such alternatives exist. From both an economic and a public-health perspective, phasing out mercury vapour lamps is a good-news story for councils.
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