Science News - May 19, 2004

Mongolia’s environment undermined by gold fever

Zeb Hogan Traditional cultures are coming into direct conflict with modern mining, which also threatens local ecology.

When the Soviet Union dropped most of its economic aid to Mongolia in the early 1990s, 30% of the nascent nation’s gross domestic product (GDP) vanished almost overnight. Mongolia quickly responded by shrugging off communism and embracing capitalist reforms. The cash-poor country is now mining its natural riches, including one of the world’s largest unexploited gold deposits, but scientists who recently visited the country worry that it may be digging itself into some long-term environmental problems.

“There is almost no environmental regulation,” says Sudeep Chandra, a postdoctoral researcher at the Center for Limnology at the University of Wisconsin, Madison. “There are laws on the books, and mining companies are supposed to do environmental impacts and then some remediation, but there is no local enforcement.”

Chandra is part of a scientific group studying the impact of mines on Mongolia’s rivers. They have been examining placer gold mines in the Selenga River system, which drains into Lake Baikal, the world’s largest freshwater body. Baikal contains approximately 20% of the world’s fresh water and more endemic species of plants and animals than any other lake.

During placer mining, large barges with enormous shovels dig 30 meters or more into the riverbed and remove the rock. The gold is then mechanically extracted, and the fill is then simply dumped back into the hole. In the forested, mountainous Yeroo region, tributaries with mining activity had turbidity 15 times higher and suspended sediment concentrations 7 times higher than the river’s main tributary, says John Stubblefield, an associate researcher at Case Western University. He has been collaborating with Chandra to measure the effects of mining. In the broad floodplain region of Zamar, total suspended sediment concentration increased as much as threefold downstream of mining pits, with occasional spikes to much higher readings.

When fine sediments fall out of the water column, they change the ecosystem of the river bottom and alter the composition of benthic invertebrates. Plus, sediment load correlates well with levels of phosphorous, a nutrient that causes eutrophication and may threaten species in decline, such as the world’s largest freshwater salmon, the Hucho taimen or “tiger of the river”.

“It’s really crazy to go in and rip up a stream. I think we as a society are beyond that now,” says Glenn C. Miller, director of the graduate program in environmental sciences and health at the University of Nevada. Miller is an expert on mines in the western United States and spent last summer examining mining activity on the Russian side of the Selenga watershed. “It’s not even the Mongolians that that are doing it,” he adds. “It’s these outside organizations that have the technology.”

With a GDP of only $5 billion (slightly greater than the budget of Orlando, Fla.) the Mongolian government has made the country a very attractive place for international mining conglomerates, which partner with local Mongolian companies. The corporations are taxed a percentage of their earnings, and because larger companies are taxed at higher rates, large conglomerates typically break up into smaller subsidiaries to maximize profits. Industry sources state that mining is now Mongolia’s largest industry, accounting for more than 55% of its industrial output and 40% of its export earnings.

“It’s kinda’ laughable,” Stubblefield says. “We toured one of the dredges, and a worker pointed to a tiny postage stamp for remediation. It was literally 30 square meters, and surrounding it were kilometers of gravel piles.”

Although Mongolia does not allow companies to employ mercury for gold extraction, its own government officials admit that some companies use mercury illegally. And scientists attribute mercury use to locals nicknamed “ninja miners”, villagers who sneak into the gravel ponds at night and pan for gold.

Scientists worry about the long-term environmental problems Mongolia will experience when mining ceases. They cite California as an example: More than 100 years after the California gold rush, the state still spends millions of dollars annually to clean up mines.

“Mongolia is so hungry to get any kind of industry in to help pay the bills,” says Miller. “And they’re not too selective about the people who go in.” —PAUL D. THACKER