New on today's
Bulletin Board

No new announcements

Tuesday, April 09, 2002

North lagoons cleanup project begins at LANSCE

Los Alamos' Environmental Restoration (E-ER) Project Office will oversee remediation of the two north lagoons at LANSCE. The work is the second phase of a project designed to remove the legacy sludge and clay liner that contain low-level radioisotopes. The contaminants of concern include cobalt-60, cesium-134, sodium-22 and polychlorinated biphenyls.

Last year the ER project successfully removed 160 cubic yards of contaminated sludge and 60 cubic yards of liner from the south lagoon, which had a capacity of 2.6 million gallons.

The two northern lagoons were constructed in 1969 to collect sanitary, radioactive and industrial wastewater from various LANSCE activities as well as septic tank sludge from other Lab activities. They operated until 1993 at which time TA-53 was connected to the TA-46 sanitary wastewater system.

After characterization data was collected and evaluated from the north lagoons, a preliminary risk assessment was performed. "The results revealed that concentrations of the radionuclides and carcinogenic chemicals within the dried sludge and clay liner surpassed the target amounts. In a risk management decision, the Department of Energy and Laboratory ER personnel decided to move forward with an accelerated action to remove the contaminated material. The decision to do a cleanup was made instead of performing additional assessments to see if the material could be left in place, " said Gabriela Lopez-Escobedo of E-ER.

Approximately 2,300 cubic yards of sludge and clay liner will be removed from both lagoons over four weeks in April and May. The field work will be done as a team by Los Alamos Technical Associates, Philip Environmental Services and Science Applications International Corp.

Because of the presence of radioactive elements, worker safety will be a major emphasis, according to Lopez-Escobedo. A safety plan has been developed that includes:

• Those who work inside the lagoon have to wear two layers of personal protective equipment, or PPE, such as anti-contamination suits, gloves, booties and hoods
• Workers will wear respirators initially for protection against the possibility of contaminated dust
  
• Workers wear passive and real-time electronic dosimeters
• Maximum individual and maximum team cumulative dose limits have been established to limit any exposure.

Dosimeters sound an alarm if an individual receives an unacceptable potential exposure that exceeds safety standards, said Lopez-Escobedo.

When the sludge is scooped from the lagoon it is loaded into roll-off containers that each hold about 16 cubic yards of dried sludge. The containers are cleaned at a contamination reduction area, then shipped to the Area-G landfill at TA-54. Heavy equipment also used in the cleanup is decontaminated.

--John Bass

Other Headlines