.News Update 12/14/07

Chrome-6 Levels Increasing in LANL Regional Well

December 14, 2007

A new study by the New Mexico Environment Department (NMED) of Los Alamos National Laboratory (LANL) ground water data indicates that the levels of hexavalent chromium, or chrome-6, are increasing in the regional well where chrome-6 was first discovered in January 2004. The NMED LANL Oversight Bureau studied the data from the regional well, R-28. The well is located on LANL property very close to San Ildefonso Pueblo and less than a mile from the closest drinking water well for Los Alamos County residents.

LANL is required to pump water out of the well until fresh water from the aquifer is reached. Then sampling can begin. This is called well purging. The standard industry practice is to purge, at a minimum, three times the amount of stagnant water in the well before sampling.

NMED studied the purging data and the levels of chrome-6 in the well. The NMED study revealed that in all cases LANL did not purge the well enough to sample fresh water from the aquifer. But in most cases, LANL only purged less than two well volumes of water. NMED found that as more water was purged, the levels of chrome-6 increased. LANL has never properly sampled well R-28 to understand how serious the groundwater contamination may be at that location for chrome-6, as well as for other contaminants.

At LANL, chrome-6 was used to prevent corrosion in its steam plants, which generate electricity.

There are two forms of chromium, trivalent and hexavalent. The trivalent form is beneficial to the body, but chrome-6 is toxic, even from brief exposure. Chrome-6 is known to cause cancer and kidney and liver damage. The New Mexico drinking water standard for chrome-6 is 50 parts per billion. The federal Environmental Protection Agency standard is 100 parts per billion.

In January 2004, LANL discovered chrome-6 levels of 270 parts per billion in well R-28. Yet, they delayed in reporting the finding to NMED for almost two years. By December 2005, the levels had increased to over 400 parts per billion. NMED proposed a fine of nearly $800,000 for the late reporting, which was reduced to a little over $250,000.

NMED required LANL to drill two new wells to discover the direction of the plume between R-28 and the closest and most productive drinking water well for Los Alamos County residents.

At first, LANL proposed to drill the wells with organic drilling fluids and bentonite clay, which mask the detection of contaminants. Robert Gilkeson, a registered geologist and former lead consultant to LANL's groundwater protection program, urged LANL to drill the wells using only air in the area of the regional aquifer. LANL did so and now states that the two wells are a success.

Gilkeson said, "The nature and extent of the chromium plume is poorly understood. The highest levels of contamination may be on the San Ildefonso Pueblo land that is near well R-28. There is an immediate need to install many more monitoring wells and to properly purge the existing wells."

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