Groundwater in the area has shown levels of hydrocarbons, metals, nutrients and PFAS above background levels.
Ongoing Investigations
The City is required to undertake investigations in respect to these legacy issues in accordance with the statutory framework under the Contaminated Sites Act 2003 (WA). The Department of Water and Environment Regulation (DWER) is the government agency responsible for administering the relevant statutory requirements.
DWER has, pursuant to the Contaminated Sites Act, the power to classify a site if, based on relevant guidelines, currently accepted industrial standards or any other information, there are reasonable grounds to do so. The types of classification include:
| Possibly contaminated — investigation required |
There are grounds to indicate possible contamination of the site |
| Contaminated — restricted use |
The site is contaminated but suitable for restricted use |
| Not contaminated — unrestricted use |
After investigation, the site is found not to be contaminated |
| Contaminated — remediation required |
The site is contaminated and remediation is required |
The City’s investigations have been ongoing for a number of years and are conducted by qualified consultants, reviewed by an independent accredited Contaminated Sites Auditor and advised to DWER. During this period a number of sites within the investigation area have been classified by DWER.
The status of the City’s investigations can be summarised as follows:
Groundwater testing
The test results from the latest groundwater monitoring event within the investigation area (March 2021 testing) indicated that the nature and extent of the contamination have, to a large extent, been determined, with no significant changes to the contamination plume and concentrations compared to previous test results. This is an indication that the contamination plume has stabilised.
Home-grown produce testing
As part of DWER’s requirements the City tested home-grown produce for PFAS within the investigation area. The objective was to determine whether home-grown produce which may have come in contact with shallow groundwater, poses a potential health risk to consumers. A range of produce has been sampled and tested for PFAS compounds, including meat, chicken eggs, avocados, tomatoes and other fruit and vegetables. The latest of these tests were undertaken in January 2021 and the test results are currently under review by DWER and the Contaminated Sites Auditor.
The outcome of the home-grown produce testing has generally been positive. In some of the sampled produce there were no detected concentrations of PFAS compounds, while other samples indicated either concentrations below the trigger values set by Foods Standards Australia and New Zealand, or slightly exceeding these trigger values. In summary, the toxicologists’ reports concluded that, based upon the availability of home-grown produce at the relevant properties and known groundwater usage and consumption patterns of this produce, the risk to human health is considered to be acceptable. However, based on current precautionary practices adopted by the City, it is suggested that owners/residents minimise consumption of home grown produce where PFAS levels exceed the trigger values used by Food Standards Australia New Zealand.
Remediation options
The City engaged an environmental engineering firm (with an international footprint/global experience) to investigate technical options for improving the quality of shallow groundwater at/on affected properties. In the process 31 different technologies/methodologies have been identified, investigated and indicatively costed. These technologies/methodologies included:
- Soil and water treatment technologies.
- Receptor management (water filtration) systems.
- Earth and construction works aimed at “sealing off” the source site.
- Providing a replacement water distribution network.
The City is in process of undertaking a costs/benefit analyses of technologies/methodologies which have been identified as being potentially viable, with this information to be taken in consideration once Council is in position to determine long term solutions.
Soil, land gas and vapour testing
The Contaminated Sites Auditor recommended that the City continues to monitor the former landfill site for harmful vapours and soil and land gasses generally associated with landfill facilities. These investigations are conducted in accordance with a management plan and will be ongoing. At this stage test results indicate that these emissions currently are not a significant cause of concern and do not pose an unacceptable health risks to the public at large.
Ongoing investigations
In the interim, and in addition to further action required by DWER, the City is continuing its own further investigations, which include monitoring on an ongoing basis the quality of shallow groundwater within the investigation area. This includes further groundwater monitoring scheduled for November 2021 (i.e testing water samples from monitoring bores within the investigation area).
What is the timeline?
Initially it was expected that, by mid-2019, the City would have been in a position to determine liability and consider long term solutions. However, due to circumstances outside the City’s control (mainly due to the detection of PFAS – see section below “What is PFAS”), that timeframe had previously been revised to mid-2020.
However, for the following reasons, the City is not yet in a position to consider and determine long term solutions:
- DWER has also indicated that the department may consider reclassification of certain properties where scheme water is available and the contaminants of concern present only exceed potable assessment criteria.
- As a consequence DWER required further investigations into home-grown produce and private bores.
- The City has completed these further investigations and submitted the test/survey results with DWER and the Contaminated Sites Auditor.
- It is expected that the Contaminated Sites Auditor will submit a further report with DWER in the 4th quarter of 2021. DWER, in turn, will refer the Auditor’s report to Department of Health for comment and advice and will then make a final decision as to the classification (or re-classification) of properties as far as restrictions on the use of groundwater is concerned – expected to be early 2022.
Once DWER has made a final decision in relation to further/final property classifications, the City should be in a position to identify and determine long term solutions for dealing with these legacy contamination issues (including addressing concerns of affected landowners). Indications are that this may occur by the second term of 2022.
What properties may be affected?
As part of ongoing investigations, water quality of groundwater from monitoring bores and private water sources to the north of the former landfill site are being tested. The attached map shows the area within which the monitoring bores are located, which is generally between:
- Rendezvous Rd to the South;
- Queen Elizabeth Ave to the East;
- The Busselton Bypass to the North; and
- Peppermint Way to the West.
Note Lot 2, Busselton Bypass (where Stonebridge Estate is located) falls outside this area. According to information provided by the owners of this property it has been classified by DWER as "Not Contaminated - unrestricted use".
The City has reported to DWER properties that, based on available information, should have been reported in accordance with the requirements under the Contaminated Sites Act. To date DWER has classified some of the reported properties as follows:
- Contaminated – Restricted Use; and
- Possibly contaminated – Investigation required.
DWER indicated that further classifications will be considered and existing classifications may be reviewed once the further investigations required from the City have been completed.
If your property has been reported or classified you should have already been notified by the Department.
Further information in relation to properties in this area potentially affected by contamination can be found on Department of Water and Environment Regulation website.
Can I use my bore?
For properties reported and classified by the Department as "Contaminated – Restricted Use" the use of groundwater is not permitted for any purpose.
For other properties there is no change in potential risk, as groundwater should not be used for any purpose without testing. This position is supported by standing advice from the Department of Health that:
“Bore water should never be used for drinking, bathing, watering edible plants, filling swimming and paddling pools, food preparation or cooking unless it has been tested and treated to the extent necessary for the intended use”.
Therefore if your property is within the investigation area, groundwater should not be used unless it has been tested and cleared for use.
If you are only using scheme water or rain water in a tank then you should not be affected.
What is PFAS?
Recent testing has identified PFAS in the groundwater at some properties.
Per- and poly-fluoroalkyl substances, also known as PFAS, are fluorine-containing chemicals which have been used since the 1950’s for the manufacture of products that resist heat, oil and water.
In more recent times there has been concern about potential PFAS contamination of groundwater. This has primarily focused on sites where firefighting foams have been used, including at defence and airport sites, which is not the case at this site.
As the awareness of the presence of these substances is recent, testing for them at the former Rendezvous Road landfill site started from mid 2017. PFAS was identified in groundwater at the former landfill site and advised to DWER in July 2017. Since that time further testing has been conducted which has identified PFAS in groundwater at properties immediately north of Rendezvous Road. Further testing will be undertaken to determine any presence in groundwater on other properties.
There is no change in potential risk, as groundwater should already not be used for any purpose without testing.
The levels of PFAS identified are a considerable order of magnitude less than what has been identified at defence and airport sites.
Research into potential health effects of PFAS is ongoing around the world. To date there is not enough information available to definitively say what, if any, health effects may be caused by exposure to PFAS.
More information about PFAS is available from:
Can I get my water tested?
Landowners and residents who live within the investigation area can request their bore water to be tested by the City completely free of charge. To arrange for testing, or for any questions, please call 08 9781 0359.
Is an alternate water source available?
Only a small number of properties within the investigation area have been using shallow groundwater. The City has completed construction of a water distribution mains along the eastern end of Rendezvous Road. As a result all properties within the investigation area have access to scheme water.
In respect of some of the properties within the investigation area DWER has advised the landowners/residents that they should not use shallow groundwater until investigations are completed. The City may, as an interim measure until investigations have been completed and upon requests from these landowners/residents, consider providing temporary assistance for accessing water.
Other long term solutions may be put in place following completion of investigations.
What other action is the City taking?
In compliance with the requirements under the Contaminated Sites Act the City reported in May 2007 to DWER the former landfill site as a suspected contaminated site. This site has since been classified as “Contaminated – Remediation Required” and registered with DWER and on the public record accordingly.
City Officers have been in regular contact with landowners and residents since detailed testing of groundwater samples in the area commenced in 2016, and will continue to do so.
The City will continue placing information on its website and updating that information as considered appropriate.
I have concerns, what can I do?
You can contact the City or the Department of Water and Environmental Regulation.
Who regulates contaminated sites in WA?
The Department of Water and Environmental Regulation.
They can be contacted for further information.