Edwardstown, 1102 South Road
Ground (bore) water contamination
In August 2011 the was EPA notified that groundwater contamination at the site of 1102 South Road, Edwardstown (on the corner of Daws and South Roads), had moved offsite and had the potential to affect nearby properties in the area.
As a precaution the EPA is advising residents and commercial/industrial property owners with bores or groundwater wells not to use bore water for any purpose until further notice. Mains water and rainwater tanks are not affected.
The contaminants identified in the groundwater 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 EPA has started working with the previous and current site owners to determine the extent of the contamination and a testing program has been developed in consultation with health experts and engineers.
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.
The EPA will keep the local community informed of progress on this webpage and FAQs will be updated with further information as it becomes available. Residents in the affected area have received a letter from the EPA advising them not to use bore water until further notice.
Technical reports on this investigation are available on the EPA's Public Register. For information on how you can view or obtain a copy, click here.
For general information on groundwater contamination and the safe use of borewater, click here.
Frequently asked questions
How did the EPA become aware of the contamination?
A notification relating to groundwater contamination at the site was received by the EPA on Wednesday, July 27 2011. As a result the EPA required additional information to be provided. Information received on Thursday, 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 happens next?
Further investigations will be required to determine the extent of the groundwater contamination.
The EPA has started working with the previous and current site owners in the last week to determine the extent of the contamination and a testing program will be developed in consultation with health experts and environmental consultants.
While the first priority is to delineate the potential underground spread of the groundwater contamination, the testing program is also likely to include some vapour testing at selected locations to assess any impact on air quality.
What is the contamination?
The contamination comprises 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.
For more information on the chemicals of concern, please refer to the public health fact sheet, Benzene: health effects, from SA Health.
How long has the contamination been present?
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.
Can I use the bore water for any use?
The bore water in the area should also not be used for drinking, irrigation or any other domestic uses until further notice.
Hydrocarbons are a widespread contaminant of groundwater around the world. SA Health consistently advises all South Australians not to use bore water unless they have had the water adequately and frequently tested and it is shown to be safe for its intended use.
If you are outside the affected zone, you should still have your bore water tested. Even if these bores are not affected by industrial pollutants, bore water can be contaminated by other sources such as historical agricultural and horticultural activities and fuel storage. It is also possible for bore water to be unsuitable for use because of the presence of naturally occurring chemicals.
How can contact with these chemical substances occur if they are in groundwater (bore water)?
Exposure occurs through using contaminated groundwater for drinking or cooking, and in showers, swimming pools and gardens (via ingestion, inhalation or through the skin).
Exposure can also occur if the chemicals migrate through the soil pore spaces to the ground surface, and then find their way through cracks and holes in the slab, floor or walls of the building. If ventilation is low, vapours may then accumulate within building spaces and be inhaled by persons in the building.
Where can I get my bore water tested?
There are several testing facilities in South Australia that can undertake bore water testing, such as the Australian Water Quality Centre. Please ensure the facility you choose has NATA accreditation. The cost of water sampling does vary however, it starts from approximately $250-$300 (including GST) per sample bottle.
How many bores are present in the area of concern?
There are few registered bores present in the area of concern. As the requirement for licensing of well permits was only introduced in 1990, and given the high groundwater quality and shallow depth in the area, it is likely that a number of unregistered bores may also be present.
How did the contamination get into the groundwater in the residential area?
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.
How can the contamination affect health?
The effects on human health depend on a number of factors, such as how long people may be exposed, and how much of each chemical is present. Other factors include a person’s health and age.
This is very likely to only be a concern if prolonged exposure has occurred in the long term (decades).
Can I eat my fruit and vegetables?
If you have been watering your fruit and vegetables with bore water, the health advice is that you should not eat them until you have had your bore tested and it is deemed fit for use.
The Department of Health issues a standard advice that bore water should never be used for drinking, cooking, watering edible plants or filling up swimming pools, unless it has been tested by a specialist laboratory. Specific advice is available from SA Health Scientific Services.
What if the fruit tree roots are in the aquifer?
While mains water and rainwater tanks are not affected by groundwater contamination, caution is recommended with any fruit trees that may have roots that tap into the aquifer.
In your area the depth of groundwater varies from 2-4 metres. Botanic Garden staff have advised the EPA of the following average root depths of the fruit trees:
- cherry trees: root depth very shallow
- citrus trees: root depth 30-50 cm (the top metre)
- stone fruit trees: root depth 50 cm (the top metre)
- avocadoes: root depth similar to citrus
- mulberry/figs/pome (including pears and apples): root depth less than 2-3 metres but if a large tree the roots maybe deeper
- pecans/nuts: potentially extends below 4 metres
- grape vines: have very long roots that are likely to travel to groundwater.
This information is based on plants being grown in soil conditions found in the domestic and agricultural environs. If you are concerned about your fruit tree(s), please contact the EPA.