Chromium plume updated

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Investigators may have found the middle of the contamination

By Roger Snodgrass

Los Alamos National Laboratory reported “the highest observed” levels of the contaminant chromium VI in the regional aquifer under Mortandad Canyon.


In an interview this morning Danny Katzman of the lab’s environmental stewardship project said this morning, “We could be looking at a plume that’s stationary.”


In its update on the first readings from a new well in Mortandad Canyon, the laboratory said the first samples show a level that is 16 times higher than the New Mexico drinking water standard, and twice as high as previous elevated readings a little farther down the canyon.


The purpose of the test well at R-42 was to try to define the size, boundaries and direction of the plume of the contaminant that is thought to have originated in the main administrative area of the laboratory prior to 1972.


Katzman said models and calculations pointed to the location as a likely spot for either finding the backside or the heart of the plume.


“We’re not surprised to hit closer to the middle,” he said.


Another well in Sandia Canyon, one canyon north, will add an additional piece to the puzzle, since it is designed to investigate an area in the regional aquifer below where an intermediate well has found elevated readings. Some indication of the tail of the plume may be discerned after the first samples are collected from that system in February 2009.


Two more wells are coming on line, farther down gradient from the well that made the original detection, to help trace a front edge of the plume and see how quickly it might be moving.


Katzman said the fact readings have not gone up at R-28, where chromium levels eight times the state drinking water standard were first detected, may mean there’s not that much movement down there.


“It doesn’t worm around in snakelike fashion down in the regional groundwater,” he said. “This is very porous and permeable area.”


The chromium probably originated in a chromate compound that was used to treat cooling water at a power plant in that area. Blow-down discharges containing a corrosion inhibitor, potassium dichromate, from a cooling tour were reported at a rate of about 60,000 gallons a week.


This effluent went into Sandia Canyon and is thought to have migrated into the neighboring Mortandad Canyon and found a fast pathway through the thick tuff and granite crust of the mountain and into the regional aquifer.


Since the chromium was detected in early 2005 and brought to the attention of regulators and the public at the end of 2006, it has brought a great deal of attention to the groundwater characterization and monitoring project at Los Alamos National Laboratory.


In 2007, a National Academy of Sciences report found that the lab’s plan was “not adequate to provide early identification of potential contaminant migration with high confidence.”


Robert Gilkeson, a geologist whose alarms about inadequate groundwater protection at the laboratory led to the NAS study, continues to review every groundwater document from the laboratory.


In an e-mail Thursday he said the new results from R-42 “proves an immediate need to install new monitoring well” to replace at least 10 surrounding regional wells, “because of mistakes that cause these wells to hide detection of the chromium plume and other LANL contaminants.


Under prodding by the New Mexico environment department and persistent criticism from watchdogs and hampered by inadequate funding from the administration and Congress, the laboratory expects to complete a full report on the Sandia Canyon infiltration.


“A lot of wells are happening real fast,” Katzman said.