The purpose of this seminar is to present the approach and results of preliminary groundwater and contaminant transport modeling at the Sydney Coke Ovens / Tar Ponds site - one of the Canada's most well known contaminated sites. Steel-making was conducted at the site for about 100 years, and releases from an associated coking operation have led to widespread metals contamination in soil, coal tar deposits in overburden and bedrock, and the accumulation of 700,000 tonnes of tarry sediments in an adjacent tidal estuary. Two major corrective actions (early- and mid-90's) were halted for technical reasons and public resistance, adding greatly to the notoriety of the site. In recent years, the site has received national media attention due to the detection of contamination in an adjacent residential neighborhood and public outcry for government to purchase contaminated properties.

The modeling was conducted during the past year, as part of a larger investigative effort intended to support development of the final site corrective action plan. The discussion of the modeling will be preceded by an overview of site history, and a summary of the site conceptual model, including: contaminant source zones, properties of hydrostratigraphic units and surface/groundwater interactions. Modeling results will be presented and indicate that groundwater discharge to the network of streams across the site is a powerful influence on contaminant migration, and tends to limit the extent of contaminated groundwater. An outline of follow-up modeling will also be presented. This work will evaluate the process of groundwater discharge in more detail, in recognition of its importance in corrective action for the site.