"Because this pile is so large and because we are so few in this remote region, they may be thinking they can save millions of dollars and justify their actions to stabilize this pile in place next to the river," Weisheit said. "Well, they would be wrong to think this way. Losing this pile to a big flood or the river's migration could affect Los Angeles as much as it would affect us here in rural Utah."

Sarah Fields, coordinator of the Nuclear Waste Committee of the Sierra Club Glen Canyon Group, said, "For thousands of years this tailings pile will remain toxic and radioactive to humans and animal life. In the scale of hundreds of years, it is inevitable that a catastrophic flood will consume this pile and devastate the down-river environment."

The environmental groups say the Colorado is also threatened — but not so dramatically — from human waste reaching it from boom towns in California and Arizona.

They say fast-growing areas there have the largest concentration of people in America that use septic tanks. They say overloaded systems are allowing high levels of nitrates to seep into the river and efforts to upgrade wastewater systems there are hampered by lack of federal support.

Also, the groups say that toxic ammonium perchlorate is trickling into the river from a former military facility near Henderson, Nev.

"Our tests last year found that perchlorate levels in winter lettuce irrigated by the Colorado were four times higher than the EPA's recommended safe dose for a glass of drinking water," said Bill Walker, vice president of the Environmental Working Group.

"The cropland irrigated by the river produces most of the lettuce and other produce sold nationwide during the winter months," he said, "which means that perchlorate is not just a local or regional problem but a concern for every American."

Wodder with American Rivers said, "The problems identified here all require immediate action, but those should be just the first steps towards a comprehensive restoration effort." She added, "We call on the nation's leaders to take the next step and develop a binding cleanup plan to ensure that the Colorado River can meet the many demands placed on it for generations to come."

---

E-mail: lee@desnews.com