U.S EPA finalizes determination of water quality violations in Los Alamos County, New Mexico

The U.S. Environmental Protection Agency (EPA) issued a final designation decision on December 9, 2024, that stormwater discharges from Los Alamos National Laboratory (LANL) and Los Alamos County are contributing to violations of water quality standards and that these discharges require a National Pollutant Discharge Elimination System (NPDES) permit under the federal Clean Water Act (CWA).

According to a press release from Amigos Bravos, an environmental nonprofit, the exceedances for some pollutants are tens of thousands of times greater than the water quality standards.

This action from the EPA comes as a result of 10 years of advocacy and legal challenges brought by Amigos Bravos, represented by Western Environmental Law Center, to force the agency to address high urban stormwater pollution in Los Alamos County.

As required by the Clean Water Act, New Mexico set standards to ensure the state’s rivers, streams and lakes are clean enough to allow the public to use these waters for drinking, swimming, boating, and other activities, and to support healthy populations of fish and wildlife.

To ensure these standards are met, the Clean Water Act requires the EPA to regulate stormwater runoff when that runoff is making the water unsafe.

“After almost a decade of advocacy we are pleased that EPA has responded to our petition and determined that toxic storm water discharges to tributaries to the Rio Grande on the Pajarito Plateau must be more strictly regulated,” said Rachel Conn, deputy director of Amigos Bravos, in a press release. EPA has taken an important step in regulating toxic discharges into the Upper Rio Grande which will protect the communities that depend on clean water for drinking, recreation, and ceremonial purposes. While we are pleased about the final designation, EPA is limited in what they can do by the 2023 US Supreme Court’s Sackett vs EPA decision which leaves many of the smaller waterways across the state inadequately protected.”

PCB levels in Los Alamos County

The New Mexico Environment Department’s (NMED) data show exceedances of the state’s PCB human health water quality limits.

PCB levels in Los Alamos Canyon are more than 11,000 times greater than the New Mexico Human Health water quality criteria and 51 times greater than the New Mexico Wildlife Habitat water quality criteria.

Sandia Canyon shows PCB contamination more than 14,000 time greater than the New Mexico Human Health water quality criteria and 66 times greater than the New Mexico Wildlife Habitat water quality criteria.

According to a press release, PCB levels in Pueblo Canyon are more than 3,500 times greater than the New Mexico Human Health water quality criteria and 16 times greater than the New Mexico Wildlife Habitat water quality criteria. These three drainages are all heavily influenced by urban stormwater runoff.

“While EPA took an important step forward today in regulating these small waterways on the Pajarito Plateau, there is more work to do at the state and federal level to ensure downstream communities are protected from the impacts of unregulated discharge of pollutants to our waters,” said Andrew Hawley, senior attorney for the Western Environmental Law Center, in a press release. “EPA’s designation of so many miles of streams as merely conveyances, reducing them to nothing more than pipes that carry pollutants downstream, shows the need for strong state action to develop a surface water permitting program to protect these important water bodies and a complete rethinking at a national level of how we protect water quality, and the communities, fish, and wildlife that depend on clean, healthy watersheds.”

Other exceedances of standards in Los Alamos County

According to a press release, the state’s 303d/305b report documents many more exceedances of standards – for a variety of pollutants and locations.

Pajarito Canyon is impaired for gross alpha radiation, aluminum, PCBs, silver, cyanide, mercury, and copper.

Mortandad Canyon is high in PCBs, copper, and gross alpha radiation pollution. LANL’s own documents confirm these findings and identify urban runoff as the culprit for many of these pollutants.