Western Kentucky University
Landfill Contaminant and Fluorescent Dye Interference Project
Institution
Western Kentucky University
Faculty Advisor/ Mentor
Priscilla Baker
Abstract
Tracing using fluorescent dyes is a practice used to map the flow of groundwater, using dyes that fluoresce at known wavelengths of light. The two particular dyes tested in this project were eosine and sulphorhodamine B. When using fluorescent dyes in a chemically diverse environment, such as a landfill or other contaminated situation, they will occasionally exhibit a fluorescence point lower than is scientifically acceptable. For example, in one particular landfill trace, the dye peak of eosine was found at 523.2 nm, 12.8 nanometers below eosine’s typical fluorescence. This degradation of fluorescence was hypothesized to be caused by a chemical reaction between the eosine and a contaminant that permanently changed its chemical structure. Three substances were chosen to test against both dyes: trichloroethylene, hydrogen peroxide, and bleach. These tests were intended to determine if these substances reacted with the dyes to such an extent that their fluorescence could no longer be detected and/or quantified. The experiment showed that in the case of hydrogen peroxide, samples showed a decrease in the concentration of dye over time. Since hydrogen peroxide is used in groundwater remediation, this evidence would recommend not using these two dyes in an area where remediation has taken place.
Landfill Contaminant and Fluorescent Dye Interference Project
Tracing using fluorescent dyes is a practice used to map the flow of groundwater, using dyes that fluoresce at known wavelengths of light. The two particular dyes tested in this project were eosine and sulphorhodamine B. When using fluorescent dyes in a chemically diverse environment, such as a landfill or other contaminated situation, they will occasionally exhibit a fluorescence point lower than is scientifically acceptable. For example, in one particular landfill trace, the dye peak of eosine was found at 523.2 nm, 12.8 nanometers below eosine’s typical fluorescence. This degradation of fluorescence was hypothesized to be caused by a chemical reaction between the eosine and a contaminant that permanently changed its chemical structure. Three substances were chosen to test against both dyes: trichloroethylene, hydrogen peroxide, and bleach. These tests were intended to determine if these substances reacted with the dyes to such an extent that their fluorescence could no longer be detected and/or quantified. The experiment showed that in the case of hydrogen peroxide, samples showed a decrease in the concentration of dye over time. Since hydrogen peroxide is used in groundwater remediation, this evidence would recommend not using these two dyes in an area where remediation has taken place.