As part of a continuing process to locate and investigate possible sites of contamination, the Jet Propulsion Laboratory has uncovered and demolished an aged dilution chamber that was part of a storm drain system used more than 30 years ago.
Several weeks ago, a construction crew discovered the old storm drain system while repaving a road in the eastern portion of the Laboratory near the arroyo. The chamber contained liquid and a black, sandy sludge material.
Analysis of the sludge revealed traces of carbon tetrachloride (13,400 parts per million) and lesser amounts of other solvents, metals. Trace cyanide was measured at 0.5 parts per million. The removal and disposal of all the waste material was handled according to federal, state and local requirements.
Once workers removed the dilution chamber they discovered an even older seepage pit underneath it. This seepage pit is believed to be one of 35 possible contamination sites in the area round the Laboratory that JPL officials have identified for future investigation. All new construction sites at JPL are routinely examined for possible signs of contamination. Seepage pits were used to dispose of a variety of material during the 1940s and 1950s when JPL was a U.S. Army ballistic missile facility.
Last year, JPL contributed $1.125 million to the City of Pasadena for the construction of a temporary treatment plant that will decontaminate four water wells in the arroyo.
News Media Contact818-354-5011