Date of Completion


Embargo Period



Lanbo Liu, Glenn Warner

Field of Study

Natural Resources


Master of Science

Open Access

Open Access


This study was conducted to evaluate trends in MTBE contamination in groundwater and the rate of dissipation of contamination at gasoline stations in Connecticut following the January 2004 Ban of MTBE in gasoline. Statistical evaluations were conducted using pre- and post-ban data for 22 gasoline stations (83 monitoring wells), representing a range of geologic, hydrogeologic and anthropogenic conditions in Connecticut. The Wilcoxon Signed-Rank test for comparison of mean pre-ban and post-ban MTBE concentration for each site supported a decrease in concentration after the ban at 18 of the 22 sites. Dissipation of MTBE was further supported with the analysis of individual monitoring wells, which showed a decrease in MTBE in 68 of the 83 monitoring wells. Using data from the first two years after the ban from wells exhibiting a decrease in MTBE since the ban (68), the MTBE dissipation was modeled as a first order rate process. An average dissipation half-life of 7.3 months was calculated. The first order models developed using data from the first two years after the ban reasonably predicted observed conditions four years after the ban.

Appendix A Contents.pdf (65 kB)
Appendix A Contents

Site Data Tables.pdf (298 kB)
Site Data Tables

MTBE Trend Plots.pdf (372 kB)
MTBE Trend Plots

Appendix B Contents.pdf (68 kB)
Appendix B Contents

Site Descriptive Statistics Histograms and Box Plots.pdf (1612 kB)
Site Descriptive Statistics, Histograms, and Box Plots

MTBE Site Trend Plots.pdf (321 kB)
MTBE Site Trend Plots

Appendix C Contents.pdf (66 kB)
Appendix C Contents

Mann Kendall Summary Table.pdf (41 kB)
Mann-Kendall Summary Table

Mann Kendall Test Data Sheets.pdf (121 kB)
Mann-Kendall Test Data Sheets

Appendix D Contents.pdf (66 kB)
Appendix D Contents

Semi-Log Trend Plots of MTBE Concentration.pdf (338 kB)
Semi-Log Trend Plots of MTBE Concentration

Major Advisor

Gary A. Robbins