Edwardstown, 1102 South Road
Groundwater Prohibition Area
Groundwater in this area is contaminated and the EPA established a Groundwater Prohibition Area (GPA) on 9 January 2018. A maximum fine of $8,000 may be issued if groundwater is extracted from the 1st (0–8 m below ground level), 2nd (0–15 m) and 3rd (0–26 m) Quaternary aquifers in certain parts of this area (please see map below). Deeper uncontaminated aquifers are exempt from this prohibition. Residents are encouraged to contact the EPA if they are unsure how deep their bore is.
In 2007 the EPA was notified that groundwater contamination at 1102 South Road, Edwardstown (on the corner of Daws and South Roads) had moved off site, and had the potential to affect nearby properties in the area.
In August 2011, the EPA advised residents and commercial/industrial property owners with bores or groundwater wells not to use bore water for any purpose until further notice.
The contaminants identified were petroleum hydrocarbons and include benzene. These chemicals are essentially fuels and oils associated with fuel storage and vehicle maintenance. Once in the soil, they can move down to the water table and contaminate groundwater.
At this stage, the contamination is suspected to be the result of a former leaking underground petrol tank.
The current site owners have liability for the site contamination and a testing program has been developed in consultation with health experts and engineers to determine the extent.
The area is bounded by South Road to the east, Daws Road to the south, Carramar Avenue to the west and Dunorlan Road to the north.
Technical reports on this investigation are available on the public register.
Letters to residents
- Groundwater prohibition area August 2017
- Map of area under investigation 6 August 2011
- 9 January 2018, Edwardstown GPA, Government Gazette, pg 18
- Determination report December 2017
Frequently asked questions
How did the EPA become aware of groundwater contamination coming from 1102 South Road Edwardstown?
A notification relating to groundwater contamination at the site was received by the EPA on 27 July 2011. Further information received on 4 August 2011, enabled the EPA to determine there may be a potential risk to off-site properties within the neighbourhood.
The EPA was originally informed about on-site groundwater contamination at this location in 2002. At that time, work was undertaken to remediate the site, including the removal of underground fuel storage tanks.
The notification received in July 2011 has been the first to the EPA since May 2003.
What are the chemicals of concern?
The contaminants of concern in the groundwater are chlorinated hydrocarbons, such as, perchloroethene (PCE), trichloroethene (TCE), dichloroethene (DCE) and vinyl chloride (VC), and petroleum hydrocarbons.
PCE and TCE are common industrial solvents and were used widely as dry cleaning fluids, degreasers and metal cleaners. DCE and VC are generally present as the result of the degradation and breakdown of TCE.
Petroleum hydrocarbons and benzene are liquid chemicals that readily flow and evaporate when released to the environment. Depending on how the chemicals were added to the soil, and the geology of the underlying soil and rock, it is likely that these chemicals migrated through the pores in the soil, dissolved in water and then flowed down gradient from the source or became present through breakdown chemical reactions.
Petroleum hydrocarbons like benzene are lighter than water. The hydrocarbon that is dissolved in water will migrate with the groundwater in the general direction of groundwater flow.
The chemicals of concern in the groundwater are petroleum hydrocarbons and includes benzene. These chemicals are essentially fuels and oils associated with fuel storage and vehicle maintenance. Once in the soil, they can move down to the water table and contaminate groundwater.
It is likely that the contamination is associated with historical leakages and spills associated with the use and storage of petroleum hydrocarbons at the site.
At this stage, the contamination is suspected to be the result of a former leaking underground petrol tank that EPA records show was removed in 2000.
For more information on the chemicals of concern, please refer to the SA Health fact sheets on chlorinated solvents, benzene and TCE.
Can I use bore water?
The groundwater (bore water) in this assessment area is contaminated and should not be used for any purpose. Water from mains and rainwater tanks are not affected by this contamination and home-grown fruit and vegetables are safe to consume, provided they are not being watered with contaminated bore water.
Is there a soil vapour issue associated with the contamination arising from contaminated groundwater?
Works undertaken by environmental consultant AECOM during May and June 2016 focused on an area of approximately 1,340 properties in southeast Edwardstown and Ascot Park. All properties in the assessment area are considered to be safe, with predicted concentrations below 2 µg/m3 of TCE for indoor air.