Reuters) - Some 3 million gallons of toxic wastewater, triple previous estimates, have poured from a defunct Colorado gold mine into local streams since a team of Environmental Protection Agency workers accidentally triggered the spill last week, EPA officials said on Sunday. The discharge, containing high concentrations of heavy metals such as arsenic, mercury and lead, was continuing to flow at the rate of 500 gallons per minute on Sunday, four days after the spill began at the Gold King Mine, the EPA said. An unspecified number of residents living downstream of the spill who draw their drinking supplies from...