Dingley 53X Environmental Audit
Michael Seignior of BlueSphere was engaged by the Shell Company of Australia Limited (Shell) to undertake a 53X audit of the former service station site located in Dingley, Victoria. Groundwater at the site was contaminated (predominantly) by petroleum hydrocarbons, including some light non-aqueous phase liquid (LNAPL). The groundwater contamination plume was found to extend beyond the southern site boundary onto the adjacent Lower Dandenong Road reserve, but not beyond the southern extent of the reserve. Groundwater was also contaminated by nitrate, which may have originated from on-site sources as well as diffuse regional sources. A number of groundwater remedial technologies were identified, with a series of LNAPL recovery events conducted, including a mobile MPVE pilot trial. The extent of soil contamination was delineated by a combination of traditional intrusive investigation in addition to the application of in-situ Laser Induced Fluorescence (LIF) drilling.
The primary human health risk drivers for the site were found to be associated with vapour intrusion, given the volatile nature of the chemical contaminants present. Subsequent quantitative human health risk assessment found that these risks were acceptable and / or could be appropriately managed. Pursuant to clause 19 of the SEPP (GoV), the EPA determined that groundwater pollution at the site has been cleaned up to the extent practicable and the Site is within a Groundwater Quality Restricted Use Zone (GQRUZ). The environmental audit report was subsequently issued incorporating a Statement of Environmental Audit.
Benefits to Client
- A polluted site was successfully remediated to the stage where it could be used for a range beneficial uses, as determined by an EPA appointed environmental auditor.
- No ongoing groundwater monitoring (post the environmental audit) was required.