Environmental site assessment, remediation and groundwater monitoring for statutory environmental audit: 190-192 New Street, Brighton, Victoria
Summary of works
ESG Environmental Pty Ltd (ESG) was engaged by Radela Nominees Pty Ltd to undertake an Environmental Site Assessment (ESA) of a former service station and garden centre for a proposed high density residential development, incorporating a two level basement car park. The 855 m2 site previously operated as a service station for approximately 60 years. A blacksmith occupied the southern portion of the site in the late 1920s.
A comprehensive site history desk top study (Phase 1) was initially undertaken to identify issues of potential environmental concern at the site. This information was then used to develop detailed soil and groundwater sampling and analysis plans for intrusive investigations. The intrusive soil and groundwater investigations (Phase 2) were designed to provide site coverage as well as targeting identified former features/activities of potential concern, particularly the former service station facilities, which were present in the initial stages of the investigations and the area where the blacksmith was previously located. The investigations involved the collection of soil samples from over 90 locations across the site and the installation and sampling from 16 groundwater monitoring wells on and in the vicinity of the site.
The intrusive soil investigations identified elevated levels of petroleum hydrocarbons and metals in discrete areas in the site soils. In addition, the groundwater at the site was identified as being impacted by petroleum hydrocarbons, chlorinated hydrocarbon compounds and metals. Several phases of remedial works were undertaken at the site by ESG and included the removal of all above ground and below ground facilities, including a large capacity above ground water tank (used in the former garden centre), seven USTs, a triple interceptor pit, two sub-floor hydraulic hoists, buildings and concrete hardstand surfaces.
A human health and ecological risk assessment was undertaken for the residual contamination following site remediation. To mitigate the risk of potential adverse impacts to site occupiers a soil vapour barrier was required to be incorporated into the development. This culminated in an EPA Clean Up to the Extent Practicable (CUTEP) determination being achieved.
As part of EPA’s CUTEP determination, ESG undertook groundwater monitoring during and post development in accordance with ESG’s prepared GQMP.
All works were conducted without safety, health or environmental incident or injury.
Project highlights
Client: Radela Nominees Pty Ltd
Client contact: Mr David Grodski
Duration: 2011 – 2016
Specific issues / problem solving
- In-house trials and on-site treatment of lead impacted soil prior to disposal off-site. This allowed for the soil to be reclassified at a lower waste category with a significantly less disposal cost
- Distinguishing between off-site and on-site sources of groundwater contamination thereby avoiding the potential for further assessment and/or remediation
Key services
- Desk top study investigation
- Soil and hydrogeological investigations
- Statistical and risk based assessment of contaminants of concern
- Groundwater modeling
- Development of soil vapour mitigation system
- Removal of service station infrastructure and hydrocarbon impacted soils
- On-site treatment of lead impacted soils
- Hazardous materials survey
- Preparation of Site Management Plan (SMP) for on-going management of soil vapour mitigation system and future site excavations
- Preparation of Groundwater Quality Management Plan (GQMP)
- Groundwater monitoring for GQMP
- Reporting for Audit requirements
Benefits
- Implementation of cost effective site clean-up to allow site redeveloped
- Essentially no restrictions on the use of the land for residential purposes
- No requirement to clean up contamination that migrated off-site
- Achieved closure on groundwater monitoring