Slag from the steel making process
has been produced at the Sydney Steel Plant since 1900. Reports
indicate that the annual output by 1954 was approximately 300,000
tonnes per year. Historically, slag was dumped into the Muggah Creek
estuary resulting in significant changes to the shoreline of Muggah
Creek and the South Arm of Sydney Harbour (Figure 5-2).
An area of slag disposal and waste disposal is referred to as the
“High Dump” and is located west of the plant area, between
the Scrap Storage Area and Muggah Creek. For the purposes of this
study, the High Dump has been defined as shown in Figure 5-1, and
occupies approximately 10 hectares, or 15 percent of the infilled
The High Dump is the most visible result of filling operations,
reaching a height of 30 metres at its peak. Prior to 1989 dumping
at the SYSCO site was not monitored, and large quantities of waste
materials were disposed on the High Dump, including derelict equipment,
demolition debris, office waste, wastewater sludge, petroleum debris,
varnish, waste oil, storage tanks and other wastes of unknown quality.
Interview responses regarding the High Dump invariably included
the phase “anything imaginable”.
Other process wastes such as Mill Scale (a carbonaceous material
that flakes off the steel blooms in the Reheat Furnace), blast furnace
flue dust, caster slag, and open hearth slag were also disposed
in the High Dump at one time or another. Since 1989, an effort was
made to segregate waste disposal, and divert inappropriate materials
from the High Dump.
The Industrial Approval for the site contains a stipulation that
calls for SYSCO to prepare a plan to address the cleanup of “hydrocarbon
contaminated sludge on the high dump”. While efforts were
made to divert continued disposal of such materials in the High
Dump, a comprehensive remedial plan was not implemented.
Sediment from the process sewer located immediately south of Ferry
Street, was periodically dredged from the line (Section 5.3.3).
The resulting sediment was excavated and removed to the High Dump
for disposal. While testing of the sewer lines in 1993 indicated
that the sewer line sediment did not contain PCBs, existing PCB
contamination in the Tar Ponds may have been removed coincidentally
and deposited in with the sewer line sediment in the High Dump.
The potential, therefore, exists that sediment with low concentrations
of PCBs has been deposited in the High Dump at some point.
The results of testing performed by JDAC in 2000/2001 indicate
that three borehole locations, MCES-001-MWB, MCES-002-MWB, and MCES-007-MWB
are located within this area. Soil samples collected from these
boreholes exceeded the CCME industrial guideline values for specific
heavy metals (arsenic, chromium, thallium and vanadium), EPA 625s
(semi-volatile compounds such as naphthalene), PAHs, HCNs, and EPA
624 (solvent-type compounds).
One surface soil location, MCES-001-SS is also located in this
area. The surface soil collected from this location exceeded the
CCME commercial guideline values for certain heavy metals (chromium
and thallium). Many of the metals identified in the JDAC analyses
were likely associated with slag fill. As discussed in Section 4.2,
previous studies have been shown that metals in slag tend to pose
a low level of environmental risk (CRA, 2001).
It is noted that the metals identified as exceeding guideline values
in soil were not present in the groundwater at levels above the
drinking water guidelines. This agrees with the results of leachate
tests performed on many samples of blast furnace slag that indicate
the highly immobile state of metals in slag.
Five monitor well locations; MCES-001-MWA (B), MCES-002-MWA (B),
and MCES-007-MWB are located within this area. Groundwater from
these wells exceeded the Canadian Drinking Water Quality Guideline
values for iron, EPA 625, PAHs and HCNs. These contaminant groups
are consistent with coal tar contamination. It is noted that the
groundwater is not used as a source of potable water