Mercury in gold mining
Why should I be aware of this?
In Asia, Latin America and Africa, there are tens of thousands of mining sites which use as much as 1,000 tons of mercury each year. The mercury not only ravages the nervous system of miners and their families, but also travels thousands of miles in the atmosphere, settling in oceans and river beds in Europe and North America and moving up the food chain into fish. :)
Mercury in gold mining and health
Small-scale gold mining is the second-worst source of mercury pollution in the world, after the burning of fossil fuels. And China is the largest user of mercury in gold mining.
Environmental and health impact if mercury is most evident in mining regions like Central Kalimantan, on the island of Borneo where extensive tropical forests have been converted to a virtual desert. Villagers say fish populations have dropped by 70 percent. The Galangan gold mining site stretches several miles, stripped of trees and dotted with mercury-laced ponds.
As mercury has a relatively high vapor pressure, a significant amount vaporizes and would be in the air. Continuous exposure to this air would mean ingesting a significant amount of mercury. The most dangerous thing about Mercury is that the lungs readily absorb the vapors.
All about mercury in gold mining
Mercury is a neurotoxin that science clearly shows threatens pregnant women, their fetus and those who eat large amounts of fish. It is a global air pollutant and its continued use in gold mining threatens millions of people all over the world.
The history of mercury use in gold mining goes back to the Romans who forced slaves and criminals to extract gold and silver with mercury. By the 20th century, though the big miners replace mercury with cyanide, small-scale miners continued because it's easy to use, fast, and cheap and leaves the gold cleaner than traditional panning.
Source of mercury
Earlier mercury used to be supplied from Spain, Algeria, China and Kyrgyzstan, but most mines have since shut down and China only supplies its own market. So mercury comes from the leftover stockpiles of shuttered mines or the dozens of companies in Europe and the United States that recycle the metal from old light bulbs, batteries or industrial waste, according to the U.N. and the Zero Mercury Working Group.
According to reports most countries import much greater quantity of mercury than actually needed for legal uses. The excess amount is sold to the miners through the black market. Some Mercury compounds are used ase poison and assaninations around the world have been documented by acute mercury poisoin, usually in extremely high doses or extremely volitile compounds such as dimethylmercury, which is so toxic that even a few microliters spilled on the skin, or even a latex glove, can cause death within a matter of hours.
As the liquid metal passes through brokers and even criminal gangs on its way to a gold mine, it is very difficult to track them. A flask of mercury can originate in Spain, be sold to brokers in India, go on to popular transit points like Singapore or Vietnam and then get dumped in Indonesia.
According to experts it is impossible to estimate the number of people killed or disabled by mercury are impossible to nail down, experts say. But miners in Indonesia, the Philippines, Colombia, Guyana, Zimbabwe, Tanzania and Brazil are found to have mercury levels up to 50 times above World Health Organization limits, according to a 2006 U.N. report. Symptoms such as reduced motor skills, fatigue and weight loss are routine at mining sites, according to the U.N.
The U.N. has spent $7 million in six countries, including Indonesia, to educate miners and gold shops about mercury. The European Union agreed earlier this year to ban mercury exports from 2011.
What can I do?
- Always use latex gloves when working with mercury
- Avoid storing mercury in aluminium and use tightly closed containers.
- Always put a layer of water on top, unless it is charged mercury.
- Always avoid heating mercury or amalgam in an enclosed space.
- If it is necessary to heat mercury, do so outdoors.
- Do not breathe the fumes.
- Mercury destroys aluminium. So never bring the two in contact.
- Avoid spilling mercury as it is very difficult to clean up.
- Never try to distill (retort) Mercury in a glass retort.
- The United States alone exported nearly 498 tons of mercury in 2007, up from 378 tons in 2006. It mostly was sent to Canada, Suriname, Hong Kong and Mexico, according to the U.S. Geological Survey.
- The trade in mercury for gold mining has gone underground in the last five to 10 years and is very secretive. The companies dealing mercury would never eveal the names of their customers and end users.
- Already, 83 percent of mercury in the U.S. is believed to come from abroad, according to the U.S. Environmental Protection Agency, and 44 states have issued health advisories about eating contaminated fish.
- Mercury is easily found at most mining sites worldwide. In Africa, miners buy it in small plastic bags stored in Tupperware containers or Vitamin C tubes. In Peru, it is sold in dental shops.