What we do know is that they get trapped in fractures in the rock and when groundwater flows over them, it dissolves some of the material making it possible for contaminants to be released into the groundwater over a long period of time. By characterizing the variability of the rock, they are discovering more about the processes that control the migration of contaminants in groundwater. This information is crucial to the design and implementation of complex remediation strategies. An Environment Canada scientist studies rock fractures in an Ontario quarry. Their results show that the properties of rock are highly variable and influence the movement of contaminants.
Some types act as a sponge, storing and releasing contaminants at various times.
Large fractures provide pathways for contaminant transport, primarily in the horizontal direction, and evidence suggests that biological conditions in the subsurface may naturally degrade some of the contaminants. The research has produced detailed, descriptive data of the site that will be used in computer models to assess the effectiveness of various remediation methods. Because the Smithville site is similar to many contaminated sites on the American side of the Niagara River, this research will help scientists and environmental managers in Canada and the United States understand the potential for contaminants to migrate into this international river and eventually into Lake Ontario, and assist in preventing it.