By Thom Mason, Director of Los Alamos National Laboratory
During the Manhattan Project, the nation’s urgency to develop a weapon that could win World War II led to environmental decisions that have had long-standing consequences. That is why the Department of Energy Environmental Management and its contractor N3B continue to work to clean up legacy waste in Los Alamos.
This important cleanup work will continue for many years, however, cleanup has also yielded many success stories, returning once-contaminated land to a condition that is safe for the community once again. Acid Canyon in the Los Alamos townsite is one of those successes.
Recently, several news outlets reported the findings of a report, compiled with the assistance of an activist group, on legacy plutonium contamination in Acid Canyon. The articles relied heavily on the messaging by the activists without giving important facts. For example, the articles did not explain the science behind applicable environmental standards, the fact that the Department of Energy has consistently made the same data public or why the canyon could both have legacy plutonium and be safe for recreation.
Prior to 1951, chemical and radioactive liquid wastes, including solvents, metals, plutonium, uranium, tritium, and other radioactive materials, from the Laboratory’s former Technical Area 1 — in the area around Ashley Pond — were discharged directly into a tributary informally called the "South Fork." This area became known as Acid Canyon because the industrial waste line was called an “acid” line.
The Laboratory’s former TA-45 was located at the top of the South Fork of Acid Canyon and served as the radioactive liquid waste treatment plant and vehicle decontamination facility for the Lab. The plant operated from 1951 through June 1964, treating the waste and discharging the remaining liquids from the mesa top down the canyon to the stream channel.
By the late 1960s, the federal government began cleaning up Acid Canyon. In 1967, it was transferred to Los Alamos County, and by 2001, the cleanup work had returned it to a condition that was safe for people and the environment.
Today, Acid Canyon is a well-used recreation area. It continues to be tested for legacy contamination, but extensive data collected there for decades has consistently shown it is a safe place to enjoy the outdoors.
The Department of Energy and Environmental Protection Agency set conservative standards for all types of contamination, including plutonium. The agencies consider the concentration of contaminants, the total exposure an individual might receive, and the risk of cancer from such exposures.
The levels reported in the media are consistent with the data that the Department of Energy has recorded and made publicly available on Intellus. Unfortunately, what the media didn’t report was that that the levels are below what the DOE and EPA say requires further cleanup. The levels are well within the agencies’ defined safe exposure ranges at less than 0.1 millirem/year, which is many times lower than the DOE public dose limit of 100 millirem/year.
To help put this level of exposure in perspective, the average person living in the Los Alamos area receives about 400 millirem per year of radiation from non-Laboratory sources like radon, and about 300 millirem per year from things like average consumer products and medical and dental procedures.
Furthermore, studies confirm that, in the event of a wildfire in Acid Canyon, the potential airborne release of contaminants would not pose a danger to the community. In September 2015, Los Alamos Fire Department and Santa Fe National Forest personnel completed a prescribed burn in Acid Canyon. One air monitoring sampler was placed on the north side near Orange Street and another on the south side at the Pajarito Environmental Education Center. All sampling results indicated there was no measurable difference between airborne radionuclide levels before, during and after the controlled burn.
I want to be clear that legacy waste cleanup and monitoring remains a major priority for the DOE and the Laboratory. We are committed to act as stewards of our environment as we execute our mission in accordance with all applicable environmental requirements. Along with our partners at N3B, we will continue our important work of collecting environmental samples not just on Lab property and in Acid Canyon, but also further afield in places such as downstream locations along the Rio Grande.
As we do, we will remain transparent with our workforce and the public regarding any potential environmental impacts caused by our past and present work.
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