Processing plant PFAS investigation and risk

Challenge

The client has operated the facility located in rural Victoria, as a processing plant for product from off-shore oil and gas platforms in Bass Strait. The site includes four gas processing plants and a crude stabilization plant. It also has a helicopter airport and fire training facility where Aqueous Film Forming Foam (AAFFF) was used. A major fire event in 1998 also resulted in the release of large quantities of fire water and foam to the environment.

Routine monitoring of groundwater quality at the site identified Perfluorooctanesulfonic acid (PFOS) at low concentrations, sufficient for Environment Protection Authority (EPA) to require further investigations.

PFOS is one of many Per- and poly-fluorinated alkyl substances (PFAS) found in a range of products including AFFF.

Solution

In response to the EPA requirements for further information, the client engaged consultants (including Anthony Lane, now of SLR) to advise on an appropriate response to the EPA notice.

A staged program of investigation and risk assessment was designed and implemented including groundwater, surface water and soil on site and extending off-site across private and public lands.

A tiered risk assessment process was used to adaptively guide the detail of the investigations, given the potential for rapidly escalating scope using a conventionally phased approach. Initial management responses of isolating sources and cutting-off exposure pathways to offsite receptors was adopted.

Impact

The investigation and management response is in progress in compliance with EPA expectation.