EPA says Los Alamos County contributing to LANL's polluted runoff

Nov. 26—Stormwater runoff is carrying contaminants from Los Alamos County's streets, rooftops, parking areas and other hard surfaces into nearby canyons that connect to the Rio Grande and should be federally regulated, the U.S. Environmental Protection Agency said in a preliminary decision.

The EPA's initial decision, which seeks to end nearly a decade of legal tussling between the county, regulators and clean water advocates, will have a 90-day comment period after it is published in the Federal Register. Then the agency will issue a final decision.

The county has resisted developing systems to filter stormwater that has picked up heavy metals and other contaminants from roadways, buildings and parking lots. It has appealed the EPA's rulings multiple times.

County officials indicated Friday they are weighing their options on the agency's latest action.

"We are thoroughly reviewing the EPA's initial revised designation decision," county spokeswoman Julie Williams-Hill wrote in an email. "We will submit our formal response during the comment period as provided by the Federal Register."

Tainted stormwater is a common problem in urban areas, but here it is magnified by Los Alamos National Laboratory discharging polluted runoff into arroyos and canyons.

The EPA says runoff from the lab and other parts of the county contain mercury, copper, nickel, cyanide, radiation and polychlorinated biphenyls, cancer-causing chemicals known as PCBs. These toxins can be carried into the Rio Grande, which is used for drinking water and irrigation, the decision says.

Several years ago, the state Environment Department pegged PCBs at 14,000 times the level deemed safe for human health in Sandia Canyon and 11,000 times the limit in Los Alamos Canyon.

The lab has a separate permit that covers polluted discharges from its industrial activities. Still, the lab claimed some of its runoff exceeds pollution standards because the town's contaminated stormwater flowing onto its sites.

This prompted a water advocacy group in 2014 to file a petition with EPA to determine whether Los Alamos' urban runoff warrants regulation.

"They [lab officials] were basically blaming some of their noncompliance on upstream urban contamination," said Rachel Conn, deputy director of Taos-based Amigos Bravos. "So we said, fine, then let's get that urban stormwater regulated as well, and we filed a petition."

Los Alamos' population is well below the 50,000-person threshold that automatically triggers a federal stormwater discharge permit, so the pollution must be shown as high enough to call for the permit, Conn said.

After receiving the petition, the EPA ruled the urban stormwater was polluted enough to require a discharge permit, but former Gov. Susana Martinez's administration disagreed and challenged the agency's decision, Conn said.

Since then, Gov. Michelle Lujan Grisham has voiced support for regulating polluted runoff coming off the Pajarito Plateau, Conn said.

In December 2019, the EPA again issued a decision saying Los Alamos' storm runoff was highly contaminated and needed a discharge permit. Because New Mexico is one of three states not authorized to regulate polluted discharges under the Clean Water Act, the EPA must do so.

The county filed an appeal with the federal environmental review board, which upheld the EPA's decision. The county then took its case to a federal appellate court, which also rejected its effort to override the EPA.

Still, doubts continued to swirl around the issue, causing more delays.

The EPA's authority to regulate stormwater fell into question when the agency's head under the Trump administration drastically narrowed the type of waters that could be federally protected.

After the Biden administration took over, the new EPA head briefly restored a broader scope of waters that could be protected. Then the U.S. Supreme Court in May ruled in the Sackett v. Environmental Protection Agency case that waterways — whether a tributaries, streams or canals — must be relatively permanent to be deemed a legitimate arm of a U.S. water and merit federal oversight.

The court's ruling disqualified storm-driven or ephemeral waters, including those flowing down slopes, which some thought would take the county off the hook.

However, the EPA has interpreted the court's decision to mean that while some canyons themselves aren't federally protected, they are funneling the stormwater to the Rio Grande, which qualifies for safeguards, Conn said.

In its decision, the EPA refers to some canyons as conveyance channels, suggesting the polluted runoff is going directly from the plateau into the river. Other canyons are relatively permanent tributaries that fall under federal protection, the decision says.

In both instances, the stormwater must be treated, it says.

The storm runoff contains some of the same pollutants that already contaminate the canyon's waters and in amounts that exceed water quality standards before entering the canyon, the decision said.

Conn said some paved areas go right to the edge of the canyon, acting as spillways during rainstorms. Roads collect many types of pollutants, including from tailpipe exhaust, tires leaving a rubbery residue and lawn-care chemicals washing onto the pavement, she said.

Building retention ponds is a common way to capture stormwater, Conn said, but the county also should explore creating bioswales — i.e., ditches designed to collect stormwater — rain gardens and green roofs as ways to reduce the runoff.

And officials shouldn't balk at the cost, she said.

"Los Alamos County is a wealthy county," Conn said. "it's not too much to ask ... for them to install simple best management practices using green and natural infrastructure to clean up the polluted stormwater."