Mortandad Canyon chromium plume may be wider than expected

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By Tris DeRoma

Chromium levels five times the acceptable state limit was detected in an injection well located in Mortandad Canyon at a chromium spill on Los Alamos National Laboratory property.

The spill, located in the western part of the Pajarito Plateau in the eastern section of LANL property, has been monitored since its discovery in 2004. The injection well was supposed to mark the spill’s outermost boundary.

Last year, David Rhodes, director for the office of quality and regulatory compliance at the Environmental Management Office in Los Alamos, described the plume as being circular, and about a half-mile in diameter, according to a 2016 Los Alamos Monitor article.

Members of Nuclear Watch New Mexico discovered the chromium level numbers in a search of a public database maintained by LANL.

The aquifer the spill is located under Sandia and Mortandad canyons. It serves Los Alamos, Santa Fe and the Española Basin.

“It’s serious and unexpected,” said Nuclear Watch NM Operations Director Scott Kovac. “Here’s another example of more places where we’re going to have to spend money that we hadn’t planned on. It’s going to come from some other part of the lab’s cleanup budget.” 

The figures show that the chromium plume is beyond a projected boundary.

“The location of the particular well, Chromium Injection Well 6 (CrIN-6), was chosen because LANL thought that it would be on the edge of the chromium groundwater plume where detection samples would be below the New Mexico standard of 50 ug/L, or in other words on the boundary of what legally requires treatment,” a statement released by Nuclear Watch said. “Given this new information, if this new well is used to inject treated water, it will help push the contamination beyond Lab boundaries instead of blocking it.”

The data shows seven samples taken at the well over a two-day period. Levels of chromium ranged from 247.24 ug/L to 259 ug/L. ug/L is a unit of density, micrograms per liter. “1” ug/L means “one part per billion.” The EPA defines a part in this case as one drop of water in a billion drops of water, about what an average swimming pool contains. The acceptable state limit for chromium is 50 parts per billion. Measurements taken at the plume have ranged as high as 1,000 parts per billion. 

Since 2004, LANL has taken measures to halt the chromium spill, which is located in an aquifer 900 to 1,000 feet below Mortandad Canyon Contractors for the lab have been installing a network of injection and monitoring wells, within the plume and around its projected boundary to keep it from spreading into nearby San Ildefonso Pueblo and elsewhere. 

The CrlN-6 well, when it comes on line, will inject clean water into the aquifer, creating a barrier of clean water around the spill. Nuclear Watch said because of the new data, LANL needs to change its plan.

“CrIN-6 is currently the last proposed injection well, while injection wells one through five are already active. The new data indicates that the leading edge of the plume passed CrIN-6’s location some time ago. Injecting treated water into it now will only serve to push the plume farther east toward San Ildefonso Pueblo and the Buckman Wells that the City of Santa Fe relies on for a third of its drinking water,” a statement from Nuclear Watch said. 

According to Nuclear Watch Director Jay Coghlan, the data further bolsters the group’s argument that the Department of Energy and the New Mexico Environment Department need to rework its 2016 consent order. The order is a blueprint of cleanup criteria and milestones LANL and the DOE Environmental Management office needs to adhere to in its waste cleanup operations around the site. 

“Timely budgets for additional urgently needed cleanup work at Los Alamos are far from being a given. The 2016 Consent Order that NMED and DOE negotiated both weakened and delayed cleanup at LANL, and allows DOE to get out of cleanup by simply claiming that it is too expensive or difficult,” Coghlan said. “But we demand that DOE find additional funding to immediately address this threat to New Mexico’s precious water resources, without robbing other badly needed cleanup projects.”

Congress is currently deciding on how much funding to provide LANL for cleanup in fiscal year 2018. Reported figures range from $191 to $217 million. 

The chromium spill was discovered in 2004. Potassium dichromate, an anticorrosive agent, was used by LANL as a coolant in a power plant that operated in or near Sandia Canyon. According to LANL, chromium came from a LANL power plant from 1956 to 1972.

Representatives at the DOE’s Environmental Management Department, Los Alamos field office could not be reached for comment.