Superfund Research Program

Determination of Toxic Metal Species in Environmental and Biological Matrices with High Energy Ion Beams

Project Leader: Quintus Fernando
Grant Number: P42ES004940
Funding Period: 1995 - 2000

Project-Specific Links

Final Progress Reports

Year:   1999 

During the past year, researchers focused on the dechlorination of compounds that are water insoluble and non-volatile and present in soils, e.g., PCB's, pesticides and insecticides, e.g., toxaphene and DDT. A two step approachhas been employed; first, the extraction of the PCB's with an organic solvent such as isopropyl alcohol (IPA), and in the second step, dechlorination of the organic compound in IPA with the Pd/Fe or Pd/C/Fe systems. The use of Pd on carbon cloth in contact with elemental iron has two advangages: The formation of iron hydroxide deposits on the Pd/Fe surface is minimized. This does not require the periodic regeneration of the iron surface with an acid wash and it also minimizes the loss of the Pd from the iron surface that occurs upon acid washing the surface.

By employing this two step process PCB's have been removed from soil in a contaminated site made accessible by the U.S. Navy in San Diego. Project investigators collaborated with a small company Terra-Kleen that specializes in the use of IPA or IPA and surfactants to extract organic compounds from soil. The complete extraction of a halogentated organic organic compound from soil depends on the type of soil and the type of surfactant used in the extraction. These extraction conditions must be determined in the laboratory before embarking on a full-scale field extraction and dechlorination process. In the future, researchers plan to build a pilot scale batch process for the extraction and dehalogenation of non volatile halogenated organics present in soil and also a pilot scale continuous process for the dehalogenation of VOC's present in groundwater.