Transport and fate of fluorinated DNAPL in a surficial clay aquitard

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There are tens of thousands of contaminated sites across Canada which pose potential human health and /or ecological risks and carry immense financial liabilities for their cleanup. Understanding the processes controlling contaminant transport and fate is necessary for assessing these risks and making informed decisions on site management and remediation. However conventional site investigation approaches generally lack resolution required for process-based understanding and therefore, reliable estimation of impacts or risks. Another impediment to understanding controlling processes is that the nature and timing of contaminant releases at most sites is very uncertain. The proposed study involves a release of a large volume of a fluorinated dense non-aqueous phase liquid (DNAPL) (4- chlorobenzotrifluoride) that occurred in 1982 into a surficial clayey aquitard as a result of a train derailment, such that the location, timing and volume of the release is known with good certainty. Therefore this site offers a unique opportunity to study evolution of an "aged" DNAPL spill that has evolved over three decades and its long-term evolution of mass and phase distribution, mobility and fate. Investigations will be conducted using advanced high resolution methods focused on the