Accession Number : ADA303249

Title :   Bioremediation: Factors Influencing Metal Ion Toxicity in a Toluene Selected Bacterial Population.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s) : Hansen, Scott D.

PDF Url : ADA303249

Report Date : DEC 1995

Pagination or Media Count : 195

Abstract : This research was a general phenomenalistic overview of the effects of metals on the respiration rates of a toluene selected microbe culture. The metals studied were copper, zinc, cobalt, manganese and iron. Relative inhibition, Cu>Fe>Zn=Co>Mn, corresponded to hydrogen phosphate binding strengths. Inhibition was found to be pH dependent; it increased with increasing pH and was shown to correlate to an increased adsorption of metal onto the cell. Zn, Cu, and Co toxicities were shown to decrease with increasing magnesium concentrations. This decrease was linked to increased magnesium adsorption and decreased metal adsorption. The magnitude of effect was related to Mg competitiveness. Sterile plating techniques were used to determine metal lethality. Results did not correspond to respiration results; however, it was demonstrated that copper's effect was lethal while zinc's was inhibitory. Increasing metal concentrations cause toxicity to increases at a decreasing rate only so long as the metal remains in solution. Metals as precipitates are no longer available to adsorb to the cell and do not affect toxicity. Toxicity was shown to be related to metal availability and how well it competed with other cations. Toxicity also depended on cell-ligand competition and how strongly the metal bound itself to the cell.

Descriptors :   *BACTERIA, *TOXICITY, *METAL COMPOUNDS, *TOLUENES, IONS, METALS, MAGNESIUM, CATIONS, ADSORPTION, RATES, POPULATION, HYDROGEN, IRON, AVAILABILITY, COPPER, STRENGTH(GENERAL), CONCENTRATION(COMPOSITION), ZINC, LETHALITY, RESPIRATION, INHIBITION, CULTURE, PLATING, MICROORGANISMS, COBALT, PHOSPHATES, STERILIZATION, MANGANESE, PRECIPITATES.

Subject Categories : Toxicology
      Microbiology
      Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE