The Narangba site contains legacy groundwater contamination, including the presence of LNAPL and dissolved phase hydrocarbons consistent with fuel loss event/s. Investigation works undertaken for Puma Energy indicated a dissolved phase hydrocarbon plume both beneath the active Puma service station and extending off-site to beneath the neighbouring residence. CDM Smith and Puma Energy worked with the Department of Environment Heritage Protection (DEHP) regarding actions that are required to limit the potential for human health and environmental harm associated, and maintain environmental values.
To assist Puma Energy in satisfying DEHP requirements, and consistent with the NEPM recommended risk-based approach, CDM Smith enhanced the level of confidence in the proposed remedial approach that was practical, warranted and scientifically defensible.
Our proposed approach was based on obtaining a sufficiently detailed understanding of the hydrogeological conditions beneath the site in order to allow for the development of a cost effective and justifiable remedial strategy for the site to protect human health and maintain environmental values both on the commercial site, for the neighbouring residential properties and for the broader environment. Our remedial plan provided information on groundwater flow contaminant transport rates across the site in order to predict the extent of groundwater impacts beyond the site boundary, based on a number of remedial scenarios. This approach in conjunction with the current risk assessment process enables the preparation of clearly defined remedial goals which are protective of human health and the environment and aims to uphold environmental values.