Summary
The EPA (as it was then known) issued a Remediation Order to PCCS on 1 July 2003. The Remediation Order declared the site, in part, as a ‘remediation site’ and in doing so determined the site represented a Significant Risk of Harm (‘SRoH’), as defined in the Contaminated Land Management Act 1997.

The Remediation Order effectively required the preparation of a Remedial Action Plan (‘RAP’) that addressed the SRoH issues and the implementation of the remediation measures identified in the RAP. The Remediation Order required the engagement of a site auditor accredited under the Contaminated Land Management Act. Dr Bill Ryall (Accreditation No.9809) from HLA Pty Ltd has been engaged as the site auditor.

The two main areas of concern for the EPA consist of the migration of air borne dust containing lead and the migration of lead, zinc, cadmium and manganese from the site via the surface water and groundwater.

Remedial Action Plan (RAP)
The RAP addresses the significant risk of harm issues, based on the current industrial site usage, as required in the EPA’s Remediation Order. The purpose of the RAP is to document the possible extent of contamination on-site relative to SRoH, address these contamination issues and provide recommended remedial actions so that the site no longer represents a SRoH and is suitable for ongoing industrial land use.

As part of the generation of the RAP, all available historical information and contamination data was examined. In addition 16 on-site groundwater wells were installed during October 2003 and a comprehensive analysis program implemented. The review of data revealed the major pathways contributing to SRoH at the site, in its current non-operational state, are considered to be:

• Surface water overflows from dam systems, generally only associated with significant rainfall;
  
• Dust from the northern waste disposal areas (known as the slag stockpiles); and
  
• Groundwater migration.

Note that soil contamination is not considered a SRoH issue based on the current site usage however contamination of the soil will be addressed in the development of the total site remediation strategy.

Slag Mound Covering
The closure of the on-site operations and the implementation of short term dust mitigation measures have yielded a 72-95% reduction in ambient lead in air measured by the high volume samplers located in the community surrounding the site.

The covering of the ISF slag stockpiles with an industrial grade plastic liner to eliminate air borne dust which may contribute to elevated lead in air readings in the neighbouring suburbs was completed in May 2004. A program to cover the slurry stockpiles with industrial grade plastic and associated drainage system was completed in December 2004 by GCE. Documentation certifying the covering of the mounds in accordance with the requirements of the License was prepared by GCE (product & installation) and Umwelt (stormwater drainage system) and delivered to DEC. Representatives from the EPA’s Newcastle office also inspected the mounds following completion.


Surface water and Groundwater
Post closure measures have been taken to minimise runoff from the site. The existing dam systems are being upgraded and are primarily used as storage to capture the surface run-off during rainfall events. The Effluent Treatment Plant (‘ETP’) located on-site continues to be used to treat water from these dams before discharging treated water off-site in accordance with an EPA licence.

Further surface water flow investigations continue and regular monitoring of Cockle Creek water quality is demonstrating that the on-site control measures are proving effective.

Investigations relating to the characterisation and modelling of groundwater passing under the site are nearly complete. The amount of contaminated groundwater leaving the site is relatively small and unlikely to constitute a health risk to humans or the environment.

To ensure that there is no ongoing or developing risk during the remediation program, PCCS plans to install a number of systems to collect and treat the groundwater before it leaves the site. Subject to authority approval, these systems will be installed in the near future and monitored to demonstrate their efficiency.

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