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THE IMPACT OF CADMIUM ON A MULTI-SPECIES BIOFILM DEGRADING NAPHTHALENE AND THE ROLE OF HYDROGEN PEROXIDE IN CADMIUM-BIOFILM INTERACTION

JIN, PENG
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1173750294

Abstract Details

2007, PhD, University of Cincinnati, Engineering : Environmental Engineering.
Polycyclic aromatic hydrocarbons (PAHs) are of major concern because of their toxicity to human health and to natural ecology. The co-presence of heavy metal wastes may hinder or prevent the biodegradation of some of PAHs. A macro-micro-molecular methodology was used to study the impact of cadmium on a multi-species biofilm degrading naphthalene and the role of hydrogen peroxide in the toxicity-resistance interaction between cadmium and the biofilm. The impact of cadmium and hydrogen peroxide on the biofilm was studied in batch experiments; cadmium transport and distribution and the micro-environmental profiles of dissolved oxygen and redox potential were investigated with microelectrodes; and microbial community changes in the biofilm were observed using CLSM combined with fluorescence probes. Cd2+ sorption in the biofilms was a rapid and highly pH dependent process. Cd2+ started to transport into the biofilm once the contact started. Cd2+ penetrated the biofilm in less than one hour. Most sorption occurred during the first two hours. Naphthalene removal had good correlation with Cd2+ sorption. The biofilm behavior toward naphthalene removal could be divided into three phases. The minimum Cd2+ inhibitory capacity for the biofilms and the Cd2+ inhibition range were defined as 5 µg Cd/mg VS and from 5 to 10 µg Cd/mg VS, respectively. A multi-species biofilm was found to have the ability to resist external inhibitors such as Cd2+. Naphthalene removal and dissolved oxygen consumption were retarded by Cd2+ but were resumed after the retardation period. The dominant components of the microbial community switched from round/rod cells to filamentous microorganisms. However, hydrogen peroxide increased the vulnerability of the biofilm to Cd2+ toxicity. When H2O2 was present, naphthalene removal was significantly inhibited by Cd2+ and did not resume at the end of the experiment. Filamentous microorganisms, which were prolific when only Cd2+ was added, were not found to be dominant in the microbial community. A multi-species biofilm developed a resistance upon external inhibition, by making the species that are more tolerant to Cd2+ the dominant ones. However, this resistance was prevented from developing due in the presence of H2O2 which may make the biofilm more vulnerable to Cd2+.
Dr. Paul Bishop (Advisor)
165 p.
Engineering, Environmental
bioremediation; cadmium; confocal laser scanning microscopy; heavy metals; hydrogen peroxide; microelectrodes; multi-species biofilms; naphthalene; PAHs

Recommended Citations

Citations

  • JIN, P. (2007). THE IMPACT OF CADMIUM ON A MULTI-SPECIES BIOFILM DEGRADING NAPHTHALENE AND THE ROLE OF HYDROGEN PEROXIDE IN CADMIUM-BIOFILM INTERACTION [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1173750294

    APA Style (7th edition)

  • JIN, PENG. THE IMPACT OF CADMIUM ON A MULTI-SPECIES BIOFILM DEGRADING NAPHTHALENE AND THE ROLE OF HYDROGEN PEROXIDE IN CADMIUM-BIOFILM INTERACTION. 2007. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1173750294.

    MLA Style (8th edition)

  • JIN, PENG. "THE IMPACT OF CADMIUM ON A MULTI-SPECIES BIOFILM DEGRADING NAPHTHALENE AND THE ROLE OF HYDROGEN PEROXIDE IN CADMIUM-BIOFILM INTERACTION." Doctoral dissertation, University of Cincinnati, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1173750294

    Chicago Manual of Style (17th edition)

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© 2007, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.