Predicting contaminant transport pathways in the Caribou-Poker Creek Research Watershed

Abstract

In order to evaluate the impact of natural organic matter (NOM) on drinking water, the hydrology of the Caribou-Poker Creeks Research Watershed (CPCRW) was considered. The CPCRW provided an excellent opportunity to investigate contaminant transport as it relates to hydrology in a well studied, discontinuous permafrost environment. The seasonal variation of organic chemistry of three different water sources (i.e. ground water, artesian spring and stream) was studied during the course of the year 2001. This thesis comprises three chapters, each of which seeks to gain a better understanding of the contaminant transport pathways in a boreal watershed, Caribou Poker Creeks Research Watershed. The hypothesis of Chapter One was that the heavy metal Cadmium (Cd) is strongly correlated to NOM. The objective was to establish the likely sources of cadmium mobility in organic rich soils. Cadmium was selected because of its tendency to be more mobile in soils than other heavy metals. The hypothesis of Chapter Two was as follows; the chemical nature of dissolved organic matter (DOM) changes during the course of a year in a boreal watershed. The objective of this study was to evaluate the seasonal character of DOM in the CPCRW. DOM was characterized using pyrolysis-gas chromatograph/mass spectrometry (Py-GC/MS), as well as ultraviolet absorbance at 254 nanometers (UV254) and dissolved organic carbon (DOC). Finally, Chapter Three had for central hypothesis that water could be traced to its origin through a correlation of NOM fingerprints. NOM was used as a natural tracer. One hypothesis was that the water appearing on the discharge areas (north-facing slopes) was derived from infiltration at higher elevation on recharging area (south-facing slopes). It was also expected to find that surface water in downstream segments could be correlated with an upstream source, and that this relationship would change during the course of the year. The main objective of this thesis was to establish the relationship of NOM type (chemical/physical characteristic) to Cd mobilization.