Environment Department Issues Report Documenting Low Levels of Contaminants from LANL in Channel near Buckman Diversion

(Santa Fe, N.M.) The New Mexico Environment Department recently completed a report that indicates planned construction activities for the Buckman Direct Diversion are unlikely to disturb sediments containing legacy contaminants from Los Alamos National Laboratory.

The report identifies legacy contaminants in sediments near but not within construction of the diversion project.

“This report indicates construction work at the diversion site can proceed,” said New Mexico Environment Department Secretary Ron Curry. “We will continue to aggressively monitor the area and require LANL to reduce the flow of storm water into the diversion to ensure Santa Fe’s future drinking water supply is safe.”

“We thank the New Mexico Environment Department and its expert staff for working with us on this study,” said Rebecca Wurzburger, chair of the BDD Board, Santa Fe City Councilor and Mayor Pro Tem. “The Final Environmental Impact Statement for the BDD required completion of the study prior to construction of the BDD near the river. We are pleased with the study’s results, which found that the area of contamination is 500 feet north of the construction area for the BDD, and that the area where construction will take place contains levels of contamination that are either non-detectable or indistinguishable from background levels of radiation.”

NMED’s Department of Energy Oversight Bureau’s report focused on an area where construction activities at the river might disturb contaminated sediments identified in an early 2007 NMED report. One of the findings of that report indicated that the highest levels of legacy contaminants along the Rio Grande were found in the abandoned river channel near Cañada Ancha. Secretary Curry directed the bureau to assist the Buckman Direct Diversion Board to quantify possible contamination at the diversion site.

The recent characterization efforts included geomorphic descriptions and chemical analyses of sediments collected from core holes at the Buckman Landing area. NMED’s DOE Oversight bureau submitted those samples for the analysis of radiochemical and heavy and trace metals, common constituents in LANL legacy wastes. The BDD Board made arrangements for drilling and subsurface core sampling work.

Authors of the report found that contaminants were not detected or were below background levels in sediments that might be disturbed during construction of the BDD. Source of background contaminants originate from atmospheric testing of nuclear weapons that occurred between 1945 to the 1980’s and is widely distributed in the northern hemisphere.

Legacy contaminants found in an abandoned channel along the Rio Grande at Cañada Ancha and near the proposed diversion originate from operations at the lab between the 1940s and 1960s. During those years, LANL discharged radioactive liquid wastes into watersheds that drained into the Rio Grande. Periodic floods during the 1950s and 1960s from the Los Alamos watershed transported some of those contaminants to the Rio Grande. Those contaminants were subsequently deposited within the abandoned river channel.

Since then and until the Cerro Grande Fire in 2000, the frequency of flooding from canyons at LANL diminished and clean sediments along the Rio Grande have covered the contaminants within the abandoned channel. But after the Cerro Grande Fire, the frequency of floods has increased and erosion from storm water is exposing previously buried sediments and again carrying legacy contaminants from the Los Alamos watershed into the Rio Grande, just north of the diversion. Since the fire, the bureau has closely monitored and reported the conditions of contaminant transport by storm water from the Los Alamos watershed.

The department continues to work with LANL, the City of Santa Fe, Buckman Direct Diversion Board and staff, and local communities to investigate and implement efforts to reduce the flow of contaminants transported with storm water from the lab. In addition, the department is working with those agencies to increase surface water monitoring efforts and providing early warning measures to shut down the diversion of water from the Rio Grande during storm water flow into the Rio Grande from watersheds at the lab.

For more information, call Marissa Stone at (505) 827-0314.

[The NMED Department of Energy Oversight Bureau’s report can be downloaded here.]