Located to the north of the Central Slag Disposal
Area, SCU 28 comprises present and former slag quarrying and aggregate
processing areas (Figure 5-1). Clean slag has long been known as
a suitable aggregate for use as a construction fill. Heckett Multiserv
currently operates the aggregate production operation in this area.
In 1997 approximately 100,000 tonnes of aggregate were processed
Despite the fact that slag has been deposited in this area for
over 70 years, few environmental issues have been identified in
the aggregate quarrying areas. Reportedly, no drums or liquid wastes
of any kind have been discovered in the past 30 years of quarrying
(pers. comm., D. Hemmings, Heckett Multiserv). Notwithstanding this,
industrial wastes such as caster slag and blast furnace flue dust
have been deposited on top of the slag mound.
The results of testing performed by JDAC in 2000/2001 indicate
that one borehole location, MCES-003-MW, is located within this
area. Soil samples collected from this borehole did not exceed CCME
commercial guideline values. Groundwater from the same location
exceeded the Canadian Drinking Water Quality Guideline values for
certain heavy metals (sodium, chloride, barium, and iron), EPA 625,
PAHs and HCNs.
These contaminants are consistent with coal tar contamination.
Groundwater concentrations of petroleum hydrocarbons exceeded the
NSDEL Tier 1 criteria. As mentioned above, elevated levels of sodium
and chloride are expected in a marine environment, and the remainder
of the contaminants are consistent with those found in the Tar Ponds.
It is noted that the groundwater is not used as a source of potable
The majority of open space in this area is covered with granular
materials. Slopes at certain locations show signs of surface erosion.
Overland drainage in the area may present the possibility of siltation
and sediment impacts to receiving waters.