ºÚÁÏÕýÄÜÁ¿

Background

The WMF provides waste management services to the City of Bunbury, the Shire of Harvey and commercial waste operators. Other activities at the premises include waste transfer station operations and a refund point for the container deposit scheme.

The proximity of the WMF to residential areas, conservation wetlands and the Brunswick and Wellesley Rivers means that contemporary and appropriate waste management practices are essential to protect the environment and human health.

Landfilling at the site commenced in 1990. The landfill cells at the facility are unlined and, over time, the waste that has been disposed of at the facility has decomposed. Some of the components of this decomposed waste have seeped a liquid (known as leachate) into the groundwater beneath the unlined cells, which has subsequently migrated into the surrounding areas.

The department recognised the ongoing risk that the unlined cells posed to the area surrounding the landfill and imposed a requirement for all landfilling in the unlined cells to cease by 30 June 2021. The approved future cells are to be constructed with engineered liners and a leachate management system. The unlined landfill cells were required to be ‘capped’ by 30 June 2022. Capping of the unlined cells was determined to be the primary and best control available to minimise the emission of leachate from the cells.

The lots occupied by the WMF are classified under the Contaminated Sites Act 2003 (CS Act) as contaminated – remediation required. In August 2021, the department received a mandatory auditor’s report confirming that the WMF is a source of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in groundwater, which has migrated off-site to the west of the WMF.

The concentrations of PFAS identified in groundwater to the west of the landfill do not pose an immediate risk to the public, as the department understands that there are no public or private bores in the immediate vicinity of the landfill utilised for the purpose of drinking water. Other groundwater bores in the vicinity are used for irrigation and are generally not suitable for drinking water purposes. In September 2021, the department requested that BHRC engage with residents of nearby properties to the west of the site to determine whether private irrigation bores may be impacted by PFAS.

BHRC completed a doorknock of about 200 residential properties to the west of the WMF to identify private groundwater bores and their use, and offered to test bore water quality. PFAS (specifically perfluorooctane sulfonate or PFOS and perfluorohexane sulfonate or PFHxS) were detected in 12 of 75 residential bores, with concentrations in all samples below (meeting) drinking water criteria. The concentrations in all residential bores were also below criteria for non-potable uses such as garden irrigation. The findings of residential testing indicated that while there were detectable levels of chemicals in the groundwater sampled from within the residential area, the groundwater was safe for normal garden irrigation use.

As a requirement of the site’s classification under the CS Act, BHRC’s environmental consultants are continuing to investigate and monitor the impacts of PFAS and other contaminants associated with landfill leachate, in the vicinity of the WMF. A further mandatory auditor’s report, reviewing the results of additional groundwater investigations, was completed and submitted in May 2023.