Amazon gold rush leaves behind dross. The sparkle of gold dust is luring thousands of Brazilians into the Amazon rain forest. But with the miners comes pollution, violence, and disease that harm the environment and native tribes.

Aldamar Rodrigues spends his days sloshing about a muddy stream and his nights fending off malaria-infected mosquitos. Here, deep in the Amazon rain forest, Mr. Rodrigues is driven by gold fever. Rodrigues left behind the grinding poverty of rural Brazil half a year ago to look for his fortune at this jungle gold mining camp. And he's willing to work all day in muck and be felled every few weeks by malaria for a chance to unearth it.

``Everybody has a dream to strike it rich,'' Rodrigues says, taking off his mud-encrusted hat. Rodrigues is one of some 500,000 men who have fanned throughout the Amazon in what analysts say is history's biggest gold rush.

Many people say that the miners, known as garimpeiros, are heroes because they create jobs for the poor and have made Brazil one of the world's biggest gold producers.

But anthropologists say the garimpeiros, who have overrun Indian land throughout the Amazon, are decimating entire tribes, mostly with disease, but also with guns.

Environmentalists worry that the garimpeiros' use of mercury to separate gold from gravel is polluting the Amazon's rivers for years to come and contaminating wildlife.

The miners dismiss this. A hard-drinking, free-spending lot, they are gripped by visions of what gold can buy.

They are generally men with no past, escaping from the misery of rural Brazil. They settle disputes with both fellow miners and the Indians with guns.

The remote gold camps echo with tales of garimpeiros who found their fortune in muddy streams. But only a handful strike it rich. Some find a sizeable amount of gold, but most blow it on alcohol and prostitutes.

The gold rush began at the Serra Pelada open-pit in 1980. But this year it became more frenzied as Brazil's economy declined.

The miners found 140 tons of gold last year worth some $2 billion, according to Jos'e Altino Machado, the garimpeiros' spokesman. Gold traders and government officials estimate the amount to be somewhere between 110 and 120 tons. Most of the gold was smuggled out of Brazil, through wildcat camps scattered throughout the Amazon wilderness operating outside government control.

With most gold mining camps carved out of impenetrable jungle and accessible only by air, the individual prospector immortalized in last century's Californian and Alaskan gold rushes has little chance here.

Instead, Brazilian garimpeiros like Rodrigues must submit themselves to a highly feudalistic system. Rodrigues works in a team with four others. A man known as the dono supplies food and the tubing, high-pressure hoses, and electric generators they use to hunt for gold. In exchange, Rodrigues's team gives 70 percent of the ore it finds to the dono.

Getting to Rosa de Maio requires a 90-minute ride south from the city of Manaus in a single-propeller airplane. About 25 planes make the flight over unbroken forest every day, to drop off or pick up supplies and garimpeiros at the gold camp. Occasionally, a DC-3 will bring larger equipment, such as the truck, tractor, and stacks of plywood alongside the dirt airstrip.

Most of Rosa de Maio's 700 garimpeiros live in thatched huts without walls that are scattered throughout the steamy jungle.

At night, many make the 30-minute trek along a rutted dirt road to the camp's bar to celebrate a gold find.

Antonio Feijao, who runs the camp, said it is not a scene of bloodshed like other gold mining areas. ``If somebody causes problems, we ship them out the next day.''

That flight out would cost five grams of gold dust, or about $75. Garimpeiros pay for everything in gold dust, which they keep in vials hung around their necks.

Rosa de Maio's miners haven't encroached on Indian land. But the headlong search for gold has caused the invasions of tribal lands throughout the Amazon. Anthropologists say the Yanomami tribe in the northern territory of Roraima is especially vulnerable.

Environmentalists, meanwhile, charge that garimpeiros are dumping tons of highly toxic mercury into the Amazon's rivers each year and call on the government to prohibit this practice.

Ana Boische, a biologist at the University of Rond^onia, said that the mercury could soon begin entering the food chain as people eat contaminated fish, fruit, or vegetables. The most fouled waterway, she says, appears to be the Madeira River between Porto Velho and Bolivia. But this is not known for sure because the University of Rio de Janeiro is only now conducting the first study measuring the incidence of mercury poisoning.

Rubia Kuno, an environmental official in Mato Grosso State, said mercury is beginning to find its way into the Pantanal, one of the world's big remaining swampland areas. In an interview with a Brazilian newspaper, she said this could irreparably damage the Pantanal's delicate ecological system.

Last in a series. Previous articles ran Sept. 22, 23, and 26.