|
|
Notice of Clean Up Action and Orica's Response
What Does the Notice of Clean Up Action Instruct Orica to Do?
The Notice of Clean Up Action (NCUA) instructs Orica to:
- Extract (pump) contaminated groundwater to stop (contain) further spread/migration from the area
- Reduce the concentration of contamination in the groundwater in the Primary Containment Area to the maximum extent practicable
- Identify contaminant (Dense Non-Aqueous Phase Liquid [DNAPL]) source areas under Botany Industrial Park (BIP) site and the Orica Southlands site, and remove them to the maximum extent practicable
- Implement a comprehensive monitoring program to measure:
- Changes in concentrations of the contaminant plumes
- Changes in subsurface spatial distribution of the contaminant plumes
- Groundwater levels to assess the effectiveness of pumping
- Contaminant concentrations in groundwater and surface water discharges to Botany Bay and Penrhyn Estuary for protection of surrounding ecosystems
What is Orica Doing about the Groundwater Contamination?
Orica has:
- Created three different hydraulic containment areas and installed groundwater extraction wells at:
- Primary Containment Area (PCA) - McPherson Street and Southlands
- Secondary Containment Area (SCA) - Foreshore Road
- BIP Containment Line - north-west boundary of the BIP and west of the Groundwater Treatment Plant
Locations of the hydraulic containment areas (while lines)
On an ongoing basis, Orica is:
- Extracting and pumping contaminated groundwater from the Primary, Secondary, and BIP Containment Areas
- Operating the GTP to treat groundwater
- Conducting various monitoring programs:
- Groundwater monitoring*
- Surface water monitoring*
- Hydraulic monitoring*
- Air monitoring#
- Investigating contaminant DNAPL source areas and remediation/depletion technologies and options
- Liaising closely with the community and government agencies
_____________
* Groundwater and surface water monitoring results are reported as an appendix to the quarterly progress reports.
# Outcomes of the GTP stack monitoring and various ambient and soil vapour monitoring events are reported in the quarterly progress report.
_____________
Progress to Date
Hydraulic containment and operation of the GTP has resulted in:
- Effective contaminant containment at the SCA, intercepting the groundwater plume generally referred to as Central Plume (the groundwater in the area flows in a south-westerly direction), and significantly reducing the direct discharge of CHCs in groundwater into Penrhyn Estuary;
- Major improvements to surface water quality in stormwater drains (Springvale and Floodvale Drains), which run through the local industrial area (refer to figure below). This results from the general lowering of groundwater levels in the area that in turn minimises the discharge of contaminated shallow groundwater to the drains;
- Improvements to ambient air quality immediately adjacent to Springvale Drain in Orica Southlands and nearby areas. This results from the improved surface water quality in the drain;
- Significant and consistent improvement to the quality of surface water at Penrhyn Estuary (where the stormwater drain discharge) and Botany Bay with regard to CHC contamination. Surface water discharge from Springvale Drain and Floodvale Drain has historically formed the dominant contributor of CHC surface water concentrations in the estuary and bay; and,
- Management of overall human health and environmental risks assessed in the Consolidated Human Health Risk Assessment.
In addition, Orica has:
- Relined stormwater pipes between BIP and Springvale Drain, preventing the ingress of contaminated shallow groundwater into the pipes and the subsequent discharge of that contaminated groundwater into the drain;
- Removed contaminated sediments from the bottom of Springvale Drain to prevent them from being carried downstream to Penrhyn Estuary; and
- On an ongoing and increasing basis, distributed treated water for reuse by BIP and neighbouring industries (see Treated Water Recycling Program).
Aerial image of local area depicting BIP, Orica Southlands, Floodvale and Springvale Drains and Penrhyn Estuary
Groundwater Cleanup Challenges
The lowering of CHC concentrations in groundwater and the rate of aquifer cleanup from 'pump & treat' is slow, especially because DNAPL source materials continue to dissolve into groundwater plumes. As at the end June 2009, Orica has removed and destroyed 702 tonnes of CHC contamination (the equivalent in mass of about 57 large 41-seater buses) from the Botany Sands Aquifer (for an update on the total destroyed CHC volume, refer to the latest progress report). Yet, no major reduction in CHC concentrations in groundwater has been observed. This provides an indication of the scale of the groundwater contamination and the challenges involved.
Orica conducted a review of the cleanup strategy for the Botany Groundwater Cleanup Project during late 2007 and 2008 in the context of achievements under the NCUA , the status of DNAPL source area investigation and depletion projects, and the revision of the regulatory framework for the project (as raised by the then NSW Department of Environment and Climate Change and discussed at Community Liaison Committee Meetings in December 2008 and March 2009). As part of the review, Orica has completed a number of studies to improve the understanding of the scale of the groundwater contamination, including estimates of the contaminant mass in the aquifer and solute transport modelling to predict the potential cleanup duration under various cleanup scenarios. The review concluded that hydraulic containment using 'pump & treat' may need to continue for hundreds of years or until new technologies become available to improve the efficiency of contaminant removal. For further details on the Botany Groundwater Strategy Review, click here .
Regulatory Change
Upcoming Replacement of NCUA with Voluntary Management Proposal
The DECCW reviewed the regulatory framework for the Botany Groundwater Cleanup Project during late 2008 to early 2009 and decided in July 2009 to regulate it under a Voluntary Management Proposal (VMP) under the amended Contaminated Land Management Act 1997. A review of the regulatory tool came in place as initial requirements outlined in the current NCUAP are now complete. Orica will submit a VMP for review and approval by the DECCW. The VMP will outline enforceable cleanup commitments and require ongoing sharing of information with the community.
|
