Contaminated Sites

The Contaminated Sites Act 2003 defines 'Contaminated' in relation to land, water, or a site as "having a substance present in or on that land, water or site at above background concentrations that presents, or has the potential to present, a risk of harm to human health, the environment or any environmental value". A site will generally be classified as contaminated if the contamination cannot be easily removed.

Contamination of land, water, or a site occurs when a substance is present at levels higher than natural background levels, posing or potentially posing a risk to human health, the environment, or environmental values (Contaminated Sites Act 2003).

The Contaminated Sites Act 2003 was enacted to help identify, record, manage, and remediate contaminated sites across Western Australia.

A site that has been classified as contaminated may still be used for various activities where appropriate remediation and management actions have occurred. This is governed by Department of Water and Environmental Regulations (DWER).

Access to a contaminated site depends on various factors, primarily whether there is a potential health risk. For contamination to pose a risk, three elements must be present:

• Source: such as contaminated soil or groundwater.
• Pathway: a means for contamination to spread, like bore water usage.
• Receptor: individuals or communities who might be affected (e.g., residents).

Site management is tailored to each situation, as every site is unique. The risk level is evaluated based on factors like the type of land use, especially in sensitive areas like residential areas or schools.

In some cases, risks can be reduced by eliminating one of the three elements. For example, preventing bore water use in area where groundwater is contaminated removes the pathway, lowering the risk to people. Similarly, physical barriers such as fencing or removal of contaminated soil can effectively block pathways or remove sources of contamination.

If the contamination cannot be fully removed due to its extent or location, ongoing management may be necessary to control access and limit exposure.

Contamination may occur due to a number of reasons, including historical industrial use, historical landfill practices, and illegal dumping.

Depending on the source and type of contamination, it can impact the quality of the soil, air, and water.

The City works closely with the Department of Water and Environmental Regulation (DWER) who oversee the management and classification of a classified site. 

Investigating and cleaning up contaminated sites is, in most cases, the responsibility of the polluter or current site owner or local government authority.

If the person responsible for the contamination can be located, they will be required to undertake actions to remediate the site. Where the responsible person is unable to be located then the landowner or Government authority becomes responsible.

There are many ways that site contamination can be managed. There is no ‘one size fits all’ approach and each case is assessed individually.

Management will also be determined by the site classification assigned to the site. DWER has seven (7) possible classifications to sites. More information is available on Contaminated sites fact sheet 4: Site classifications and appeals.

The City of Kalamunda is carrying out ongoing works and sampling to monitor and remediate sites under the guidance of Department of Water and Environmental Regulation (DWER).

The site's classification will determine whether the site is accessible to the public and the types of works undertaken. To ensure safety, public are advised to adhere to any signage on site. This may include:

• Keeping to designated areas (i.e. pathways if present).
• Not entering areas that are fenced/barricaded off.
• No digging or disturbing the ground or soil (includes any off-road vehicle activity).
• Not disturbing any equipment or infrastructure in place that may be used for monitoring.
• Be mindful that some sites may have CCTV in the area.

Landowners, tenants, and those responsible for contamination are legally obliged to report any known or suspected contaminated sites to the Department of Water and Environmental Regulation. Visit the Department of Water and Environmental Regulation (DWER) website to report a known or suspected contaminated site.

If a site is classified as "Possibly Contaminated – Investigation Required," it will not appear on the public database. This is because the full extent and nature of the contamination have not yet been determined. Once investigations provide sufficient information to understand the contamination, the classification will be updated, and the site will be listed on the public register.

Assessing site contamination can be a lengthy process, with monitoring carried out over a long period of time to determine trends and seasonal variations. 

If a risk to public health is confirmed, DWER or the City of Kalamunda will advise the impacted community.

There are two ways to access information on contaminated sites:

• Contaminated Sites Database - This database has information on confirmed contaminated sites being managed by DWER is available online, free of charge.
• Reported Sites Register – Records all other reported sites, including those awaiting classification. To access this information, you will need to complete and submit a Form 2 - Request for information to DWER (fees apply).

Detailed information about contaminated sites, including the contaminated sites database and auditors of contaminated sites, is available on the Department of Water and Environmental Regulation’s website.