LOS ALAMOS, N.M. — More than 60 years after scientists assembled the nuclear bombs dropped on Hiroshima and Nagasaki, lethal waste is seeping from mountain burial sites and moving toward aquifers, springs and streams that provide water to 250,000 residents of northern New Mexico.
Isolated on a high plateau, the Los Alamos National Laboratory seemed an ideal place to store a bomb factory's deadly debris. But the heavily fractured mountains haven't contained the waste, some of which has trickled down hundreds of feet to the edge of the Rio Grande, one of the most important water sources in the Southwest.
So far, the level of contamination in the Rio Grande has not been high enough to raise health concerns. But the monitoring of runoff in canyons that drain into the river has found unsafe concentrations of organic compounds such as perchlorate, an ingredient in rocket propellent, and various radioactive byproducts of nuclear fission.
Laboratory officials insist that the waste doesn't jeopardize people's health because even when storm water rushing down a canyon stirs up highly contaminated sediment, it is soon diluted or trapped in canyon bottoms, where it can be excavated and hauled away.
"We are seeing no human or ecological risk," said Danny Katzman, director of the lab's water stewardship program. "We won't be surprised on occasion to see a higher than normal reading. But those higher values last for 40 minutes during a flood, and maybe two hours out of a year."
Much surface contamination, however, becomes embedded in sediment or moves down into groundwater. That subterranean migration poses the greatest long-term danger to drinking-water wells and ultimately the Rio Grande.
"When you see a child's footprints and Tonka toys in canyons where there is plutonium, there is reason to believe that a lot more work needs to be done to make the environment safe," said Ron Curry, secretary of the New Mexico Environment Department.
In 2002, the department issued an extensive cleanup order stating that waste at Los Alamos may pose "an imminent and substantial endangerment to human health and the environment." Laboratory officials accused the department of exaggerating the threat and resisted the order for several years before agreeing to a revised plan to scrub about 2,000 dirty sites by 2015.
