ALBUQUERQUE, N.M. — Farmers, towns and tribes slammed water-intake gates shut as a sludge-laden plume from a Colorado mine spill rolled down principal rivers in the desert Southwest on Monday, prompting local officials and families to demand answers about possible long-term threats from heavy metals borne along by the spill.

Colorado and New Mexico declared stretches of the Animas and San Juan rivers to be disaster areas as the orange-colored waste stream estimated to be 100 miles long churned downstream toward Lake Powell in Utah after the spill Wednesday at the abandoned Gold King mine.

The Navajo Nation, which covers parts of New Mexico, Utah and Arizona, also declared an emergency as it shut down water intake systems and stopped diverting water from the San Juan River. Members of the tribal council were frustrated during a special meeting Monday and echoed the sentiment of New Mexico officials that the federal government should be held accountable.

The 3 million gallons of mine waste included high concentrations of arsenic, lead and other heavy metals. Workers with the U.S. Environmental Protection Agency accidentally unleashed the spill as federal and contract workers inspected the abandoned mine near Silverton, Colorado.

The EPA has said the contaminants were rolling too fast to be an immediate health threat. Experts and federal environmental officials say they expect the river system to dilute the heavy metals before they pose a longer-term threat.