A coyote in Los Alamos scouts for prey.
A coyote in Los Alamos scouts for prey.

LOS ALAMOS, N.M. – With its steep canyons and watersheds emptying into the Rio Grande, numerous ancient pueblo cultural sites, and wildlife ranging from black bears to broad-tailed hummingbirds, the Pajarito Plateau creates a distinct backdrop for environmental remediation around Los Alamos National Laboratory (LANL).

In protection of that backdrop, the EM Los Alamos Field Office and its cleanup contractor, Newport News Nuclear BWXT-Los Alamos (N3B), have performed field assessments at nearly 300 potentially contaminated sites to protect various ecological receptors from soil contamination linked to historical LANL operations. Receptors include aquatic species, invertebrates, birds, mammals and vegetation.

“We’re proud of our work over the past four years, since N3B’s contract began, to protect northern New Mexico’s ecology,” said Patricia Wald-Hopkins, N3B’s human health and ecological risk assessor and a lifelong New Mexican.

“We go to each site where we’re collecting soil samples — and where we’ll excavate contaminated soil, if necessary — to identify the vegetation and wildlife that could be at risk. If wildlife isn’t present, we look for animal tracks, scat, nests and burrows that reflect a certain species,” Wald-Hopkins said. “We also look for signs of erosion and whether there’s potential for contamination to reach other receptors through contaminant migration.”

A male mule deer enjoys vegetation in Los Alamos.
A male mule deer enjoys vegetation in Los Alamos.

Following these ecological assessments, N3B environmental professionals combine their findings with the site’s soil sample results to conduct risk analyses. The analyses compare contaminant levels with state-approved risk action levels for each species identified in a given area. The site’s documented history — with information on LANL’s war-time operations — is also considered. The results of those risk analyses then drive N3B’s remediation efforts.

“Following our ecological assessments, we develop a conceptual exposure model for all ecological receptors, which tells us what risks we need to address,” Wald-Hopkins said. “If we know there’s wildlife and contaminants in soil, we look at all exposure pathways and calculate the risk of exposure. It’s a very important piece of DOE EM’s work because it connects our data to what’s actually in the field. It’s a real-time glimpse of what’s out there.”

More than half of the 2,100-plus potentially contaminated sites at LANL associated with historical operations and originally identified for investigation have been cleaned up. Areas range from small spill sites with a few cubic feet of contaminated soil to large landfills encompassing several acres.