Originating at the former Sydney Dump, cutting through the middle of the former Coke Ovens site, and ending in the Tar Ponds, Coke Ovens Brook has a heavy load to bear (Figure 5-1). For decades this stream served as the leachate drain for the Sydney City Dump, the process wastewater sewer for the Coke Ovens facility and the sanitary sewer for residential areas in Whitney Pier. Historical maps indicate that the 1902 shoreline of the Muggah Creek estuary extended up Coke Oven Brook almost to Victoria Road. The result of this historical industrial use is contamination of not only the stream bed sediments, but of the fill and groundwater adjacent to the brook.

In the Muggah Creek Phase II Environmental Site Assessment Report (JDAC, 2001), JDAC reports that the former location of Victoria Road was at grade immediately east of its present location, where it was later constructed as an overpass in the late 1950s. At that time it was moved to its present location and built up above grade with fill to construct the overpass. It is expected that fill used in the construction of the overpass was placed directly on previous ground surface. Any contaminated fill on the DOMTAR site could therefore potentially be hydraulically connected to a similar unit under the SYSCO property (JDAC, 2001).

Overburden thickness on the site varies between 5.2 to 6.7 metres, and is comprised of fill or till. The fill layers on either side of the Victoria Road overpass have a similar thickness, suggesting the possibility of a hydraulic link between the two. The contact surface of the Canso and Morien Groups is located near the eastern perimeter of the steel plant property, presenting the possibility of a geologic barrier or impediment to contamination moving toward SYSCO property from the Coke Ovens site.

Analytical results contained in the JDAC report indicate that heavy metals (arsenic, thallium, selenium, titanium, lead, copper, zinc, and vanadium) and PAHs were detected at levels that exceed the Canadian Council of Ministers of the Environment (CCME) guideline values for commercial sites. HNC and petroleum hydrocarbons were also detected, but at concentrations below the applicable guideline values.

In groundwater, heavy metals (sulphur, manganese, iron, and strontium) concentrations exceeded the Canadian Drinking Water Quality Guideline values, as did some PAH concentrations. Petroleum hydrocarbons were detected at concentrations below the applicable NSDEL Tier 1 guideline value, and PCB analyses failed to detect their presence. The extent of these impacts has not yet been determined, and no testing has been performed inside the steel plant fence line.

The No. 3 Gate House and parking is presently located within the parcel. The building is constructed of a combination of concrete and wood. Potential hazardous building material and environmental issues associated with the Main Gate House may include lead-based paints, asbestos containing material and PCB fluorescent

The majority of open space in this area is covered with granular materials. Slopes at certain locations show signs of surface erosion. Stormwater catchbasins are located throughout the area, presenting the possibility of siltation and sediment impacts to receiving waters.

The potential environmental issues associated with the Coke Ovens Brook area are related to the subsurface impacts that have been identified on the site. These include PAH, HNC, heavy metal and petroleum impacts that may extend beyond the fence line of the steel plant and may present concerns for adjacent SCUs. The No. 3 Gate House may also contain hazardous building materials.