The giant dredges drifting down the Caguán, Guainía and Yarí rivers in Colombia’s Amazon had long ago become a familiar part of the rainforest setting for the many Indian tribes living on the rivers’ banks. But for agents of Colombia’s internal security service (DAS) who traveled into the area disguised as backpackers, it was alarming to see hundreds of Colombians, Brazilians and Peruvians diving into the water with oxygen tubes, local children with harelips and other deformities and fish with grotesque ulcers on their skin.

This was illegal gold mining on an industrial scale. And the owners of the dredges—Marxist rebels from the Revolutionary Armed Forces of Colombia (Farc)—were making millions while poisoning the region’s human and aquatic population.

“The guerrillas use the gold to buy ammunition and weapons,” says one member of the DAS team, which raided dredges and seized account books proving the rebels’ ownership. “They also contaminate rivers with mercury, poison fish and expose the inhabitants to the long-term perils of lung disease, central-nervous-system disorders and birth defects.”

Colombia, officially the world’s 16th largest producer of gold with a reported production of 18.8 metric tons last year, is well acquainted with the problems of untrammeled gold extraction. Illegal gold mining—employing an estimated 60% of the nation’s 40,000 gold miners—runs the length and breadth of the nation, from the northwestern rainforests of Chocó to the southeastern areas of the Orinoco and the Amazon.

The destruction reflects that found in other Amazon areas in Guyana, Venezuela and especially Brazil, where a gold rush in the 1980s killed millions of fish and poisoned miners and Indians alike. But Colombia, battered by record unemployment, drug trafficking, civil war and a near-total breakdown of state authority, is especially vulnerable.

Mining suits many agendas

Thousands of itinerant prospectors, working with hammer and chisel in deep mountain tunnels or with high-powered pumps on river dredges, depend on the few dollars a day they make from the illegal trade to supplement meager farm incomes. Drug traffickers use gold to launder millions in profits from narcotics sales. Marxist guerrillas and their right-wing, death-squad enemies, meanwhile, sell it to buy guns and ammunition on the black market.

Colombia’s production pales in comparison to that of such countries as Brazil. (See table, Page 8.) But the special blend of poverty, criminal activity and violence here makes illegal gold mining at least as big a scourge for Colombia as it is for its far larger neighbor, which possesses two-thirds of the largely unpatrollable Amazon.

“Gold-mining operations are frequently in the hands of illegally armed groups in Colombia,” says Armando Borrero, a national security advisor in the government of former President Ernesto Samper. “That generates chaos in the sector and makes the job of ameliorating its environmental and health effects at times almost impossible.”

Environmental authorities are doing what they can. In areas the guerrillas have left or have yet to show up, officials teach both legal and illegal miners how to improve practices, and they provide cleaner gold-processing equipment. They also organize cooperatives so green technologies will be cheaper. And they supply field labs to monitor performance.

With only a few million dollars to spend nationwide, authorities here hope to reduce contamination levels so drinking water in aqueducts is safe and the water in swamps and rivers is clean enough for fishing.

But that goal, most experts agree, is an awfully long way off.

“Given a terrible situation of public [disorder] and few resources, local authorities are making an estimable effort to change the culture of gold mining and reduce contamination that is harming aquatic ecosystems and threatening human settlements,” says Carlos Alba, a mining advisor to the nation’s environment ministry. “Still, this is primarily a social problem. The challenges to its resolution are colossal.”

Gold mining damages the environment in myriad ways. Mercury, used to precipitate gold from surrounding sediments, ends up mixed with discarded materials and dumped into rivers. The product of the process, a gold-mercury amalgam, is then heated to vaporize the mercury,causing the poison to enter the environment in gaseous form. Through a process called methylation, meanwhile, mercury that is released into rivers is converted into methyl-mercury, a toxic organometallic compound that can accumulate to dangerous levels in fish. It also affects animals farther along the food chain, including the giant otter (Pteronura brasiliensis), which is threatened by gold mining in Colombia, Brazil and other Amazonian countries.

Impoverished inhabitants of river settlements who cannot afford foods other than fish suffer the health consequences. So do miners who inhale mercury vapor in the air. They become weak and experience coughing fits and memory loss in the short-term and lung disease and nervous-system disorders in the longer term. Cyanide solutions, used to separate gold from surrounding sediments in a different mining process, represent equally grave hazards. They leach into water sources, causing massive fish kills and the closing of aqueducts.

“Gold mining has contaminated the food chain with heavy metals, affected the health of workers and led to the destruction of river networks and ecosystems,” says Adam Rankin, a researcher with Agua Viva, a non-governmental organization that works on water issues.

The northwestern state of Chocó, where gold mining was begun in the 16th century using the labor of African slaves, represents a tragic snapshot of those effects. The state, home to extensive tropical lowland forests, mangrove swamps and coral reefs, is one of the world’s great storehouses of biodiversity. It has thousands of recorded vascular plants, numerous endangered animal species—including the giant anteater (Myrmecophaga tridactyla) and the manatee (Trichechus manatus)—and among the richest bird fauna in the world, with more than 100 endemic taxa.

But some 320 illegal gold-mining operations wreaked havoc there in the 1990s, says the Organization of Black Communities of the Pacific (PCN), the region’s dominant social organization. Each year, bulldozers and large mechanized shovels stripped away up to 198,000 acres (80,000 hectares) of forest to turn over the gold-rich earth. Deforestation devastated populations of wild pigs and rabbits as well as the Baird’s tapir (Tapirus bairdii) and other endangered species. Erosion and the accumulation of sediment in rivers changed rivers’ courses and reduced the penetration of light in the water, killing algae and fish.

Numerous cases of mental retardation in children from mercury poisoning also have been observed by the PCN.

Time and the growing chaos of Colombia’s civil war have only worsened the situation. In the last couple of years, some 400 guerrillas of the Farc have moved into the Urabá region of Chocó. There, they use bulldozers and dredges to expose river bottoms and search for gold, according to the DAS. Dozens of streams have been destroyed, deforestation has worsened and mining camps filled with workers—either directly employed by the guerrillas or paying taxes to them—have become breeding grounds for cerebral malaria.

Millions of dollars a year are at stake in the guerrilla group’s mining operations. “Until the army and police get together and drive the guerrillas out, environmental authorities will be banned from the area and the environment will remain a lost cause,” says a DAS agent who has taken part in local operations.

Mining authorities acknowledge that poverty often underlies the environmental problem. Gold miners who spend long hours chiseling rock in tunnels or panning waist-deep in rivers rarely make more than the equivalent of $5 a day. Schools, hospitals and other social services are non-existent for them, and child labor is common. Malaria is a constant threat. Dire need and the squalor in jungle camps and shantytowns make it inevitable that they will accept jobs in guerrilla- or paramilitary-run operations that ignore environmental and safety standards.

Mining regions are characterized by “precarious basic services and a diminished or non-existent state presence,” says a recent Environment Ministry report on the gold sector. Small wonder that even the best-intentioned efforts face long odds.

Last year, officials in Caldas closed a mine threatened by erosion. Some 300 freelance prospectors then swarmed over the site. They entered abandoned pits and used earthmovers, picks and shovels to dig deeper into the hill, erecting no structural supports. When heavy rains unleashed a mudslide in November, the hillside caved in, killing more than 50 miners underground. Authorities could do little to help. Survivors simply moved to other mines. “These are extremely poor people who roam from place to place in an effort to survive,” says Rubén Darío Barco, head of the regional environmental office. “We have no idea what happened to them after they moved away.”

Not all the news is bad.

In the Valle del Cauca, where cyanide spills from gold processing have forced the temporary closure of municipal aqueducts three times in the last two years, authorities have shut down illegal mines. They also have begun an intense program to improve the lot of both legal and illegal miners.

They have brought in instructors to teach miners how to identify promising mineral deposits. They’ve also tapped experts to reduce health and environmental risks by, for instance, controling mercury vapor and using small dams to contain cyanide. And authorities have helped create cooperatives that would eliminate middlemen, allowing miners to earn greater profits. “We want miners to work in conditions of greater equality, to improve their technical and productive capacities and boost their earnings,” says Luís Alfonso Guzmán, a forestry engineer for the state’s environmental authority.

Bolívar rainforest also affected

In the tropical rainforest of southern Bolívar, the presence of some 16,000 gold miners, at least half of them illegal, marks an ecological threat nearly as grave as that in Chocó. Mining, along with coca cultivation and timber operations, has reduced populations of the threatened spectacled bear (Tremarctos ornatus) and the mountain pig (Tayassu pecari). And widespread use of mercury in a 5,400-square-mile (14,000-sq-km) complex of swamps around the Cauca River has resulted in the loss of 85% of the fish population—including bocachicos (Prochilodus sp.) and mojarras (Aequidens sp.), both of which are consumed locally and sold on the national market.

As fishermen’s catches have shrunk, their physical health has been put at risk, according to a 1998 study by scientists from the University of Cartagena. Mercury levels in fishermen near certain swamps—as measured in hair samples—were found to be nearly twice the maximum level permitted by the World Health Organization.

But some progress is being made. A five-year project by the local environmental agency, the Regional Autonomous Corporation of Southern Bolívar, has established three centers where 200 miners will be trained each year in building state-of-the-art gravimetric machines for separating gold from remaining sediments without the use of mercury or cyanide and in using the compound thiourea to precipitate gold in a more organic fashion.

The project, which received $400,000 from the national government and is asking $2 million from the European Community, could become a model.

“We hope to move gold miners from highly contaminating techniques to semi-industrial processes that are more ecological and more technically efficient, helping both the environment and the miners’ pocketbooks,” says Miguel Angel Peñata, the Autonomous Corporation’s project director. “Given the similarity of gold-mining methods around the country, we hope the example will spread.”

While efforts at reform are already underway at various sites around the country, thanks to national funds and contributions from the German aid agency GTZ, the problem is so enormous that many experts fear it will be years before substantial improvements are felt. Says Alba, the environment ministry’s mining advisor: “This is such a tremendous problem that the state is going to have to design a coordinated, integrated policy and dedicate far more resources if it is ever to be solved.”