SÃO PAULO, Brazil — Fueled by the surging price of gold, an epidemic of illegal gold mining in the Amazon is threatening indigenous territories and other protected lands in the world’s largest tropical rain forest, according to a study published by a group of environmental organizations this week.

Analyzing data from six Amazon countries, researchers identified 2,312 illegal mining sites and 245 large-scale areas where miners have established sophisticated infrastructure, tearing down native forests and contaminating rivers with mercury as they dredge for gold and extract diamonds and coltan, which are used to make mobile phones.

“The problem is worse than at any other time in history,” said Alicia Rolla, one of the coordinators at the Amazon Geo-Referenced Socio-Environmental Information Network, known as RAISG, which published the study this week. “We wanted to give visibility to the enormity of an issue that doesn’t respect borders.”

The report compiled data from local partners, news reports and research from eight independent environmental groups that scanned satellite images, mapping mining sites in Brazil, Peru, Bolivia, Colombia, Ecuador and Venezuela.