Date of Completion

8-21-2017

Embargo Period

8-17-2017

Advisors

Dr. Timothy Vadas; Dr. Alexander Agrios; Dr. Melissa McKinney

Field of Study

Environmental Engineering

Degree

Master of Science

Open Access

Open Access

Abstract

The aim of the present study was to examine the uptake kinetics of copper to periphyton, a biofilm community of heterotrophic and autotrophic species, under freshwater and wastewater effluent exposure conditions. Copper uptake kinetic experiments were run using a constructed trickle apparatus, where short-term exposures were completed using environmentally relevant total copper concentrations. The differences in periphyton surface bound copper and intracellular uptake kinetics were observed and modeled by examining periphyton copper content, periphyton cellular binding parameters, and metal speciation based on dissolved organic matter (DOM) characteristics. First-order rate kinetics were used to analyze the differences in initial uptake rates between the different exposure waters. It was found that as the percentage of wastewater effluent increases in the exposure waters that the periphtyon total and intracellular uptake rates decrease. Reduced periphyton copper content (surface bound and intracellular) was also observed for the exposure waters containing wastewater effluent. Water quality characteristics were investigated to further analyze the effects of source water on periphyton uptake. Free copper ion concentrations were estimated by inputting measured water quality parameters and experimentally derived DOM conditional binding constants into Visual MINTEQ. An equilibrium ion exchange technique was used to investigate the exchangeable copper fractions. Kinetics modeling using the total, free ion, and exchangeable copper concentrations allowed for examination of the bioavailable copper fraction. With reduced copper contents of periphyton under exposures containing wastewater effluent, this study illustrates a positive role that enhanced wastewater effluent DOM and inorganic complexation may play in limiting copper toxicity to periphyton.

Major Advisor

Dr. Timothy Vadas

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