Surface water and Groundwater

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

Further surface water flow investigations have been undertaken in response to the Approval Conditions, and regular monitoring of discharge water quality and 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 through the site have been undertaken.  Most of the groundwater from the site passes through the Hawkes and South West Dam catchments.  To ensure that there is no ongoing or developing risk during the remediation program, PCCS have installed a boundary well pumping system for each of these two catchments, following authority approval, to collect and treat the groundwater before being discharged from site under the EPA licence. 

Any remaining uncaptured groundwater leaving the site is of a relatively small flow and does not constitute a health risk to humans or the environment.

 

Monitoring Programs and Management Plans

A Remediation Environmental Management Plan (REMP) has been prepared for the whole site.  The REMP includes the following general plans and monitoring programs to be carried out across the whole site:

- Air Quality Management Plan & Monitoring Program
- Contaminated Water Management Plan & Surface Water Monitoring Program
- Erosion & Sedimentation Protocol
- Noise & Vibration Management Plan & Monitoring Program
- Traffic & Transport Management Protocol
- Complaints Handling & Response Protocol

These monitoring reports are also required to be submitted to the Site Auditor, the Director-General for Planning (D-G) and the DECCW.  A Site-wide groundwater monitoring program is currently in place for the entire site, with sampling undertaken on a 6 monthly basis.  There are also two sets of groundwater pumps located on the western site boundary that intercept contaminated groundwater and prevent discharge from the site. 

A Remedial Action Works Plan (RAWP) has been prepared for the specific stages and or areas of the site to be remediated in order to develop robust remediation options to address the significant risk of harm, and to ensure that each part of the site is suitable for the proposed end use.  These reports have also been submitted to and approved by the Site Auditor and D-G & DECCW prior to the commencement of works in specific parcels.

Each RAWP contains a detailed Remediation Environmental Management Plan (EMP) that details the specific environmental management practices and procedures to be followed locally during remediation of that particular parcel. 

Monitoring Results Summary

Since the closure of the site, lead in air and metal concentrations in water have fallen dramatically. – For air, current levels of lead in air are around 90 percent below the levels pre-September 2003.  For the first month after closure, lead in air at Fourth Street averaged 0.07 ug/m3 compared to the annual average prior to closure of approximately 0.88 ug/m3.  Metals in discharge water are also down significantly with average concentrations of lead now 0.01 mg/m3 from 0.08 mg/m3.  In addition, cadmium concentrations have fallen from 0.11 mg/m3 to 0.06 mg/m3.

A summary of the monitoring results undertaken during remediation works to date is included below:

- Groundwater Monitoring to date indicates evidence of contamination across the site in unremediated areas and also that the contaminated water is being effectively captured by the boundary wells and is not having any off-site impact.

- The site weather station has been upgraded to record additional real time data during the remediation period.

- Parcel 1 (CWE)
? Noise & Vibration monitoring undertaken during remediation works found that noise readings were generally within the acceptable limits and that there were no adverse vibration effects.  The work has been undertaken without complaint from adjacent properties.
? Analysis of Dust Data collected during the remediation works found that readings were within the acceptable limits.
? Most of the groundwater in the CWE area has the same concentrations as in the background groundwater coming from Munibung Hill.  Monitoring following the completion of the remediation has been undertaken, and as expected showed improvements in groundwater concentrations in areas that were previously filled with waste.

- Parcel 2
? Noise and Vibration monitoring undertaken to date during remediation works found that noise readings were generally within the acceptable limits and that there were no adverse vibration effects.
? Analysis of Dust Data collected during the remediation works found that readings are generally within the acceptable limits.  For those instances where levels were above the specified criteria, specific mitigation measures were implemented.

- Parcel 3
? Noise and Vibration monitoring undertaken to date during remediation works found that noise readings were within the acceptable limits and that there were no adverse vibration effects.
? Analysis of Dust Data collected during the remediation works found that readings were generally within the acceptable limits.  For those instances where levels were above the specified criteria, specific mitigation measures were implemented.
 

 

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