Erasing the legacy of the Minamata mercury poisonings

China, the world’s biggest producer, user and emitter of toxic mercury, must invest more in the search for substitutes

Mercury thermometers and blood pressure devices are to be consigned to the museums of medical history. In late January, after four years of talking about it, 147 countries agreed on the text for the first global mercury treaty.

The Minamata Convention, named after the Japanese city that suffered severe public health problems due to mercury pollution in the mid 20th century, is due to be signed this autumn and will require countries to remove products containing mercury, including thermometers, blood pressure devices and fluorescent light bulbs, from the market by 2020, or bring them up to specified standards.

It also restricts mercury emissions from coal plants, industrial coal furnaces, smelting and concrete manufacturing. Existing mercury mines are to be closed within 15 years, and no new mines opened.

Mercury is a toxic heavy metal which damages the human brain and nervous system. Tiny amounts can cause health problems, including abnormal brain development in infants and erratic blood pressure, numbness and malfunction of the nervous system in adults. Mercury evaporates into the atmosphere and is then carried into bodies of water through rain, meaning it can accumulate in organic compounds in the food chain.

The most infamous case of mercury poisoning, in Japan’s Minamata city, came to light in the 1960s, after a local chemical factory spent 30 years dumping large quantities of organic mercury into the local bay. The pollution caused widespread illness. Half of those severely affected died within three months. Babies born to afflicted mothers suffered learning difficulties. Today, mercury poisoning is also known as Minamata Disease.

Also see: methylmercury poisoning in Japan

How will China meet the targets?

China is the world’s biggest producer, user and emitter of mercury. While experts and industry insiders agree the treaty is fairly lenient and will present few problems for China’s manufacturing industry, the recycling of mercury-containing products and controlling emissions from coal burning and smelting is a bigger challenge.

This new rules do not come out of the blue for industry. Firms using mercury have been actively making changes since international talks got going in 2009.

Zhang Hong is a consultant on chemical safety to Chinese NGO Beijing Global Village. He told chinadialogue that batteries made in China now contain no – or very little – mercury. Standards for fluorescent lights are also already very high. Mercury thermometers and blood pressure devices will not be restricted for another three to five years and, with trials of replacement products already under way, the healthcare industry has plenty of time to change.

Wang Jun, general manager of Shanpu Lighting, said that fluorescent lights bound for the American and European markets have been meeting stricter EU standards for years: “Over 80% of fluorescent lights are made in China, and we use the most advanced technology. There are no technical obstacles stopping the industry shifting from liquid mercury to amalgam.” 

However, China still has a long way to go to meet the requirements of the treaty by 2020.

More research and development of substitute products is needed, while reliable methods of controlling mercury pollution during the use and recycling of products, or from coal burning and smelting, are yet to be found.

Fluorescent light standards may be high, but there are still no suitable substitutes, says Wang Jun. In September 2011, the China Lighting Industry Association put forward three key targets, including cutting mercury content of compact fluorescent lamps (energy-saving bulbs) from 2 milligrams to 0.6 milligrams by June 2015. “We need more R&D if we’re to do that,” says Wang.

Recycling is difficult and expensive

Mercury pollution arising from the use and disposal of mercury-containing products is harder to control than emissions during manufacturing.

When mercury-containing products are thrown away, the element can make its way into the atmosphere, finding a route into rivers and lakes – and the food chain. Most consumers are unaware of mercury’s dangers and don’t dispose of products correctly. Recycling is difficult and expensive. Wang said that only four or five fluorescent light makers have high-tech mercury recycling equipment. Some leading firms and government departments are collecting lights for recycling.

“There isn’t enough recycling of discarded lights in China, and the public hasn’t been mobilised to help. Recycling of energy-saving bulbs has been virtually abandoned – NGOs and government need to act,” says Zhang.

There are also problems with mercury-free replacements.

Fluorescent lights can be replaced with LED bulbs, while electronic thermometers and blood pressure devices can be used in healthcare. This is already happening.

“But the government needs to invest in supporting R&D and promotion,” says Zhang. “Current electronic blood pressure devices can’t measure very low blood pressures, and that’s a real problem. All the emergency rooms and ambulances where the electronic devices are being tested need to keep at least one mercury device on hand.”

That won’t be the only expense. The costs of staff adjustments at manufacturers, shifts in management procedures, new equipment and teaching materials in the healthcare system, staff training and legislative changes, will all add up.

Then there’s coal. Coal burning is a major source of mercury emissions, and there is no national plan to control this, says Zhang.

In 2007, coal burning in power plants and industrial furnaces accounted for more than half of China’s mercury emissions. Oversight of China’s many small gold mines, which use mercury to extract gold from ore, is very difficult. Neither Zhang nor David Lennett, senior attorney at US campaign group the National Resources Defense Council, who worked on the Minamata treaty, are confident control measures will be effective. 

Getting a mercury deal to work
Even though the mercury treaty has been agreed in principle, the bigger challenges are about implementation and outcomes.

Critics have attacked the agreement for lacking teeth. There is no requirement for individual countries to create national plans for how they will reduce mercury emissions, for example. Zhang also points out that the treaty makes no demands about cleaning up polluted land, while Lennett says limitations on emissions of mercury to the atmosphere are unclear and timetables too lax.

Different countries have been left facing different challenges, according to Lennett. Mercury controls in the US differ between states. Unified requirements and oversight at federal level are urgently needed. In China the most serious issue is controlling mercury emissions from the smelting industry. While in India its coal burning.

Under the terms of the treaty, a global fund will be established with money from developed countries to support capacity building and technology in developing nations. Deciding how that money is allocated and used will be another challenge. In the meantime, Lennett says industry needs to start adapting, “businesses cannot wait – they need to act now, plan and change their production strategies".