ON THE RIO MADRIA, Brazil (AP), Hundreds of illegal miners dredging gold in Brazil were navigating along Brazil’s Madeira River on Friday. Researchers said that they posed a threat to the environment, including toxic mercury.

The municipality of Autazes spotted the barges this week, approximately 120 km (70 miles) from Manaus.

Although smaller groups of barges are more common along rivers in the area, the most recent collection attracted international attention when Greenpeace published images of several rows.

Hamilton Mourao, Vice President of Brazil, announced a police operation in the area. This prompted miners to leave early Friday morning and move elsewhere along the river.

Thiago Bitencourt, a miner, was dressed in a pair of shorts with flip flops. He said that 400 barges – about 3,000 people – congregated in the area, after one miner discovered gold there.

“Everybody knows everybody else. The 28-year old, whose uncles, aunts, cousins, and father were all part of the contingent, said, “We’re all friends, they’re all related.”

Wood-walled rafts with wooden walls, many equipped with satellite internet or air conditioning units, were connected together to form rows of houses along the Madeira River, a large tributary which flows into the Amazon downstream from Manaus. The barges are where miners, their families, and their pets live, eat, and work.

“We all know that we are illegal under the law.” However, we all have to provide for our families,” Gomes stated. He also said that miners had repeatedly urged politicians to legalize their activities — but in vain.

Another miner stated that a barge accumulated 60 grams of pure gold, which is worth approximately $3,500, over 40 hours of labor. Many workers worked 24 hours a days, often taking turns.

Environmentalists are concerned by the fact that miners use mercury to separate the gold from the sediment from the river bottom. This process releases toxic vapors and can spill some into the river.

Paulo Basta, a researcher at the Fiocruz science centre, stated that once it is in the river, the sediment falls to the bottom, and can contaminate fish, shrimps, and turtles downstream.

Basta stated that there is strong evidence linking mercury contamination to cognitive problems, alteration in senses, hypertension and hypertension. He also noted that miners are at high risk of being exposed.

He takes the mercury and puts it in his bag. The mercury vapor leaks onto his leg, and then contaminates him through the skin. Inhaling mercury vapor can cause serious lung damage,” Basta stated.

According to miners, they don’t release mercury into the water, which can be expensive, but instead try to reuse and recover it.

Amazonas State prosecutors called Wednesday on federal and state authorities in coordination to respond and end the illegal settlement within 30 day.

The Federal Police responded by a brief statement stating that they are aware of the situation, and were evaluating all options.

According to miners, no authorities had ever come in contact with them on Friday. They fled Autazes in fear of being arrested and continued to follow the river. Powerboats pushed the barges along, and they headed in different directions.

Local media reported tensions between Autazes residents and miners, but journalists on the scene saw many locals profiting from the arrival of hundreds upon hundreds of visitors. They sold food, diesel, clothes, and even perfume.

Mining has been a sensitive topic since January 2019, when President Jair Bolsonaro took office vowing to increase development in the Amazon region as well as to legalize certain types of currently-banned mining operations.

It is one of the many factors that drive deforestation. The trend started in 2014 and has been accelerating under Bolsonaro (whose father was a wildcat miner).