The suburb of Coogee lies 18 km south of the Perth CBD, where many of the properties in the area have historically been used for market gardening activities. Astron was engaged by Terranovis Pty Ltd who managed the Coogee residential subdivision development. Due to the previous land use activities, the Department of Environment Regulation (DER) required that appropriate Contaminated Site Investigations (CSI) be undertaken to comply with Western Australia Planning Commission (WAPC) conditions.
The CSI initially comprised a Preliminary Site Investigations (PSI) and Sampling and Analysis Plan (SAP). A Detailed Site Investigation (DSI) was then undertaken comprising extensive soil and groundwater sampling and analysis across the site.
Heavy metal (Arsenic and Zinc) and Organochlorine Pesticide (dieldrin, DDD, DDE & DDT) contamination was identified within upper soil horizons on the site. Buried asbestos was also identified at several locations.
Tier 1 & 2 Ecological Risk Assessments (ERA) were undertaken on broad-scale low-level contamination areas. Results of the ERA allowed the in-situ management of the contamination on site, negating the requirement to large-scale remediation program.
In areas where higher concentrations of contamination was identified, a Site Management Plan (SMP) and Remediation and Validation Remediation Report (RVR) were necessary to remove contaminated soils and confirm that the areas were appropriately remediated in accordance with DER guidelines and expectations.
The full CSI was reviewed by a WA Accredited Contaminated Sites Auditor and subsequently approved by the DER allowing the project to proceed to development stage.