BRASILIA, Jan 24 (Reuters) - Public prosecutors chasing illegal gold mining in Brazil's Amazon region on Wednesday opened an investigation into on-line sales of mercury through Mercado Libre, Latin America's largest e-commerce site.

The Federal Prosecutors' Office recommended Mercado Libre ban mercury ads from its platform, or inform authorities who is placing them and establish better controls over the trade in what it called "an extremely dangerous pollutant."

Wildcat miners in the Amazon use liquid mercury to agglutinate gold particles and separate them from ore and dirt when they dredge through muddy excavations in the rainforest.

Mercury pollutes the rivers and poisons the fish, a staple for Indigenous communities in the Amazon where studies show women and children with dangerously high levels of mercury in their blood.

Stopping the sale mercury, along with fuel supplies and the financing of mine prospects is part of the Brazilian government's crackdown on illegal gold mining that has surged in recent years in the Amazon.

"Mercado Libre sales platform has been used indiscriminately for trading liquid mercury, without any control over the origin of the material and the parties involved in the transactions," the prosecutors recommendation said.

Mercado Libre said it was ready to help prosecutors with their investigations into the sale of prohibited products.

"As soon as such products are identified, the ads are removed and the seller is notified, and could be banned from the platform," Mercado Libre said in a statement.

Mercury is a controlled substance in Brazil and sales are illegal if not registered stating its origin and use.

Brazil does not produce mercury, which must be imported and illegal purchases are made by Internet on platforms such as Mercado Libre, an Argentine company headquartered in Uruguay and incorporated in the United States.

Mercury poisoning can cause serious neurological damage and malformation of babies.

A 2019 study led by Fiocruz, Brazil's top biomedical research lab, found the presence of mercury in 56% of Yanomami women and children in the Maturacá region of the Amazon.

Brazil is a signatory of the Minamata Convention, an international treaty designed to protect human health and the environment, named after the devastating incident of mercury poisoning in Japan.

(Reporting by Anthony Boadle; editing by Diane Craft)