A mile-long plume of toxic, cancer-linked chromium has spread onto the Pueblo de San Ildefonso Native American community in New Mexico, raising health concerns. The underground contamination, originating from the Los Alamos National Laboratory, now exceeds state groundwater standards.
Recent sampling by the New Mexico Environment Department found hexavalent chromium levels between 53 and 72.9 micrograms per litre, above the 50 micrograms per litre limit. The plume stems from water coolant used at the lab's non-nuclear power plant between 1956 and 1972, when contaminated water was flushed into Sandia Canyon.
State and federal officials have installed wells and a treatment system to manage the plume, but the Environment Department says containment efforts have been inadequate. The Department of Energy agrees the plume is not near drinking water wells and is working with authorities to assess and remediate the site.
A planned pump-and-treat system was halted in 2023 after chromium increases were detected in monitoring wells. Partial treatment resumed earlier this year, but officials believe this allowed the plume to spread. The Environment Department has called for more aggressive action, stating the Department of Energy has not prioritised the issue.
Pueblo Governor Christopher Moquino said the community will take all necessary action to ensure cleanup and accountability. Long-term exposure to hexavalent chromium can increase the risk of lung and other cancers.
