BLOOD GOLD

THE TERM “blood diamonds” denotes the dark side of mining these precious gems, possibly in war zones, possibly financing insurgencies or warlord activities. We can add the term “blood gold” within similar contexts—and with global ecological implications.

This is described in the article “Gold’s Dark Side,” by Lizzie Wade, in the September 27, 2013 issue of Science magazine, published by the American Association for the Advancement of Science. The horror of blood gold arises in its small-scale artisanal mining around the world—and in its becoming the world’s leading source of mercury pollution.

A bit of history first. Those of us of a certain age remember science class where we enjoyed herding those elusive shiny globules of mercury around on a table top.

Mercury, symbol Hg, also known as quicksilver. Image from www.kids.britannica.com.

The only metal that’s liquid at room temperature, mercury is used in thermometers, barometers, fluorescent lamps and, no surprise, mercury switches and relays. It is also highly toxic. (See www.wp.me/p2ETap-NX for an earlier reference to this.)

The world’s worst mercury disaster arose in the mid-1950s in Minamata, Japan, on the west coast of Kyushu about 600 miles southwest of Tokyo. A local chemical plant relied on mercury sulfate as a catalyst in one of its production processes; methylmercury contaminated the waterways and nearby Minamata Bay.

Local fish and shellfish accrued elevated levels of mercury; people eating the seafood suffered—and many perished—from mercury poisoning. What came to be known as Minamata Disease affected as many as 100,000 people in the area. Even though the plant halted its use of mercury sulfate in 1968, cases of the incurable disease continue to emerge.

Tragically from an ecological point of view, mercury is also part of a straightforward means of separating gold from earth.

An artisanal miner in Peru mixes mercury into a barrel of ore and water. Image from Science, September, 27, 2013.

Mix the ore with water and add a palmful of mercury into this slurry. The mercury acts as a sponge, it and the gold forming heavy balls of puttylike amalgam.

An artisanal miner uses a torch to burn off the mercury from the amalgam. Image from Science, September 27, 2013.

Pluck this amalgam out of the slurry, burn off its mercury—and the gold remains. (Mercury vaporizes at 674 degrees Fahrenheit; gold doesn’t even melt until nearly 2000 degrees F.)

One path of mercury pollution. Image from Science, September 27, 2013.

The problem is in artisanal use of this process and its uncontrolled release of mercury. After producing the amalgam, miners discard the contaminated slurry into waterways, where its mercury accumulates in fish and aquatic surroundings. When the amalgam is burned away, mercury vapor enters the atmosphere. Once gold enters international markets, there’s no tracing it back to its source.

Sources of mercury pollution, 2010 data. Image from Science, September 27, 2013.

According to the Science article, artisanal gold mining accounts for 37 percent of the world’s known mercury pollution, the largest single category. It’s also the most difficult to control.

Banning the practice simply doesn’t work; it merely drives things underground. Another approach is persuading artisanal miners to use different processes—ones that are safer for them and the environment, more efficient and even potentially less expensive. The challenge is in bringing education and cooperation to an industry that’s inherently informal.

The United Nations Environment Programme has been the forum for the Minamata Convention on Mercury.

As for mercury, there’s the Minamata Convention on Mercury, an international treaty that’s part of the United Nations Environment Programme. Its purpose is “to manage mercury in an efficient, effective and coherent manner.” The treaty has already been signed by more than 140 nations, though full ratification is expected to take several years. ds

© Dennis Simanaitis, SimanaitisSays.com, 2013