Last page is titled: Appendix 1: DVD of Model Simulations (See DVD in Back Envelope). There was no DVD present for upload. / <p>Point Pelee National Park (PPNP), located in Leamington, Ontario, Canada experienced widespread application of DDT from 1950 until DDT was banned in Canada in 1970. vVbile DDT has not been applied at PPNP for over 30 years recent studies have shown that the compounds DDT, ODE and DDD are highly persistent in shallow soils at PPNP and often exceed regulatory guidelines set forth by the Ontario Ministry of the Environment and Environment Canada. Field study combined with numerical modelling was undertaken to assess the concentrations of DDT, DDE and DDD in groundwater and provide insight into the fundamental processes controlling the persistence and migration of DDT within former agricultural areas of PPNP. Results of one-dimensional pesticide fate and transport modelling from 1950 to 2003 using LEACHMP show that within former agricultural areas of PPNP, DDT is transformed primarily not DOE under aerobic conditions. Within the Camp Henry Orchard (CHO), half lives for the production of DDE are 30 years. LEACHMP modelling showed that adsoption was the most important process limiting DDT leaching to groundwater. The depth to the water table was found to influence DDT concentrations seen at the water table throughout former agricultural areas of PPNP, and DDT is most likely leaching to the water table slowly over time. Two dimensional saturated zone modelling using OW-WETLAND was used to test various loading scenarios based on LEACHMP simulated fluxes across the water table. Model outputs illustrated the bidirectional movement of contaminants toward both the marsh and Lake Erie, depending on the source location relative to the groundwater flow divide. Simulations showed only groundwater from deep within the aquifer would have elevated DDT concentrations in 2003 if DDT leached to groundwater between 1950 and 1970. Conversely, if DDT began to leach to groundwater in the 1990's, the model predicted that DDT was not present in deep groundwater in 2003. With continued loading, concentrations throughout the aquifer will continue to rise into the future and discharge of DDT to the marsh and Lake Erie will occur.</p> / Thesis / Master of Science (MSc)