EPA assessment area
The investigations have been focused on assessing the scale of chlorinated hydrocarbon contamination, primarily trichloroethene (TCE), in groundwater and soil vapour.
The groundwater contamination continues to move slowly northwest. To prevent exposure to the contamination in groundwater, the EPA has advised owners in the area not to use groundwater (bore water) for any purpose. To formalise this advice and to prevent bores being installed in the future, the EPA is currently consulting on establishing a groundwater prohibition area (GPA) to prohibit the taking of groundwater to a depth of 20m below ground level.
TCE contamination in groundwater is volatile and provides a source of vapour in the soil. Vapours in the soil can move upwards into buildings in a process called vapour intrusion where concentrations of TCE can build up indoors and present long-term health risks. The EPA has undertaken indoor air testing in some homes predicted to be at risk from vapour contamination coming up through the soil.
The most recent assessment, Stage 5S (seasonal), was completed in August 2023 and confirmed the groundwater within the majority of the assessment area is contaminated. The next stage of work will commence in October 2023 and aims to further refine the vapour intrusion risk and determine the extent of a small TCE groundwater plume in the northeast of the assessment area.
Chemicals of concern
Trichloroethene (TCE) is a commonly used industrial solvent, widely used as degreasers and metal cleaners. Dichloroethene (DCE) and vinyl chloride (VC) are generally present as the result of the degradation of TCE.
For more information on the contaminants, please visit the SA Health website.
The chemical substances found to be present in groundwater) have the potential to change from liquid to gas (volatilise) and move through the soil as vapour. It is then possible for this vapour to migrate and build up in underground spaces such as cellars and basements, as well as move into the indoor air of buildings. This is referred to as vapour intrusion.
Underground structures are closer to the contaminated groundwater and may increase the risk of vapour intrusion into buildings, including into rooms on the ground level. Any owners with cellars or basements should contact EPA for further advice regarding vapour intrusion risk.
Watch this animated video explaining vapour intrusion.
Selling or buying
The EPA is obligated under the Land and Business (Sale and Conveyancing) Regulations 2010 to flag an interest in all certificates of title for properties within an EPA assessment area where an environmental assessment report has been prepared.
This interest will result in a positive response on the Form 1 prepared during the sale of a property and ensures that future potential purchasers are aware that an environmental assessment has been undertaken.
This means a prospective purchaser considering purchasing a property located within the assessment area, will now observe a YES response to Question 4(c) in the EPA Statement to Form 1.
In addition to this YES response, a note will be included to refer the potential purchaser to the EPA website to obtain information in relation to this assessment area.
This is in addition to the EPA interest relating to the groundwater prohibition area that has been established in the area.
Should you required further information regarding the environmental assessment or how this relates to a specific property, please contact the EPA for tailored advice.