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Extramural Research

Grantee Research Project Results

Grantee Research Project Results

Use of Cadmium-Resistant Microorganisms in Co-contaminant Remediation

EPA Grant Number: U914958
Title: Use of Cadmium-Resistant Microorganisms in Co-contaminant Remediation
Investigators: Roane, Timberley M.
Institution: University of Arizona
EPA Project Officer: Manty, Dale
Project Period: January 1, 1996 through January 1, 1999
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1996)
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Earth Sciences



The objective of this study research project is to evaluate the ability of metal-resistant microorganisms to detoxify metal in co-contaminated (with both metallic and organic contaminants) systems to ultimately allow for organic degradation. This project addresses two questions:

(1) Can metal toxicity within a metal-contaminated soil be reduced by metal-resistant microbial populations?

(2) Will organic degradation occur in the presence of metal that was once bioaugmented with a microorganism capable of metal detoxification?


Using 2,4-D and cadmium as co-contaminants, several cadmium-resistant bacterial isolates were examined for the ability to detoxify cadmium to sufficient levels to allow for 2,4-D degradation to occur. Degradation of 500 mg Kg-1 2,4-D by the cadmium-sensitive 2,4-D degrading bacterium, Alcaligenes eutrophus JMP134, in the presence of cadmium occurred following cadmium detoxification by a cadmium-resistant isolate. The addition of one of four cadmium-resistant isolates, representing the genera Arthrobacter, Bacillus, and Pseudomonas, was found to detoxify up to 32 mg Kg-1 cadmium in pure culture and soil under laboratory and field conditions. Using genetic and microscopic analyses, the observed mechanisms of cadmium-resistance included: (1) slime layer production; (2) energy-dependent efflux; (3) surfactant production; and (4) intracellular accumulation.

Supplemental Keywords:

fellowship, cadmium, cadmium-resistant, metal-resistant organisms, organic degradation, metal toxicity, metal-contaminated soil, metal, soil, metal detoxification, detoxification, cadmium detoxification., Scientific Discipline, Waste, Water, POLLUTANTS/TOXICS, Contaminated Sediments, Remediation, Environmental Chemistry, Chemicals, Ecology and Ecosystems, Soil Contaminants, metal resistant microorganisms, contaminated sediment, remediation technologies, contaminated soil, bioremediation of soils, organic soil contaminants, co-contaminants, cadmium

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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