Ground (bore) water contamination
In June 2011 the EPA received information from Bridgestone Australia Ltd which indicated that levels of trichloroethene (TCE), a known contaminant, were above World Health Organization drinking water guidelines in an area in South Edwardstown very close to an area of previously established contamination.
TCE is an industrial solvent which was widely used in the past as a metal cleaner and degreaser.
The EPA believes that this contamination is likely to be associated with previously known contamination arising from the former Bridgestone facility at Edwardstown, first identified in the 1990s.
Bridgestone Australia Ltd has previously undertaken extensive assessment and remediation works associated with contamination originating from their former site and bore owners have been advised not to use their bore water until further notice.
Bridgestone Australia Ltd has carried out ongoing groundwater monitoring and provided the results to the EPA. This monitoring suggests that contamination is in a more expansive area than first known.
Further investigation will be required to determine the full nature and extent of the contamination.
The area now under investigation is bounded by Robert Street to the west, Oval Avenue and Flinders Street to the north, Lindsay Way and Calstock Avenue to the east and Furness Avenue and Weaver Street to the south.
The area of interest also extends to a section in Edwardstown and Melrose Park where the issuing of permits for new groundwater wells has been restricted since 2007.
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.
For more information residents can contact the EPA on 1800 729 175 or SA Health on 8226 7100.
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.
- Letters to residents, 7 July 2011
- Media release, 7 July 2011
- FAQs, updated 7 July 2011
- Map of area under investigation, 7 July 2011
How did the EPA become aware of the contamination?
The groundwater contamination in the area of southern Edwardstown is likely to be associated with known contamination arising from the former Bridgestone facility at Edwardstown, first identified in the 1990s.
Bridgestone Australia Ltd has undertaken extensive assessment and remediation works of this contamination and has previously notified the public of the contaminated groundwater, tested private bores in the nearby area and advised bore owners not to use their bore water until further notice. Since the completion of the remediation works, Bridgestone Australia Ltd have carried out ongoing groundwater monitoring and provided the results to the EPA.
In June 2011 the EPA received new information from Bridgestone Australia Ltd which indicated that levels of trichloroethene (TCE) in groundwater continued to be above World Health Organization drinking water guidelines.
What happens next?
Further investigation will be required to determine the extent of the groundwater contamination as part of the ongoing groundwater monitoring being carried out by Bridgestone Australia Ltd.
What are TCE and DCE?
TCE (trichloroethene) is a common industrial solvent and was used widely as a degreaser and metal cleaner. DCE (dichloroethene) is generally present as the result of the degradation and breakdown of TCE.
How long has the contamination been present?
It is likely that the contamination is associated with leakages and spills which occurred in the 1990s associated with operations at the former Bridgestone facility.
Historically, it was also common practice to dispose of spent solvent onto soil at a back corner of a site. Similarly leaks occurred in underground storage tanks and pipes.
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 (including GST) per sample bottle.
How many bores are present in the area of concern?
There are very few registered bores present in the area of concern. As the requirement for registration 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 these chemical substances get into the groundwater in the residential area?
TCE and its breakdown products (DCE) are liquid chlorinated hydrocarbon 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.
Liquid chlorinated hydrocarbons like TCE are denser than water, and will sink down through water until they reach an impermeable barrier. In their pure form they will then flow along preferential pathways via gravity or pool in confined areas. The hydrocarbon that is dissolved in water will migrate with the groundwater in the general direction of groundwater flow.
What happens when TCE enters the body or the environment?
If TCE is taken into the body, it is then metabolised (broken down) and eliminated from the body within days. In the environment, TCE breaks down rapidly in air and surface water but much slower in soil and groundwater. TCE breaks down into dichloroethene (DCE) and then vinyl chloride (VC) which can then degrade to other products.
How can TCE and its breakdown products 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.
Will bore water contamination affect my property value?
The presence of groundwater contamination will mean that bore water will not be able to be used from shallow aquifers at properties in the affected area. The EPA’s experience in managing other similar incidents of contamination is that property values were not affected.
It is possible that the EPA will in the future declare a bore water restriction zone. If this occurs, this information will be recorded against the certificate of titles of the properties in the affected area, to ensure that future purchasers of the property are aware of the restriction on using the bore water.
For further information on health-related queries, please contact SA Health on 8226 7100.
For site contamination related enquiries, please contact the EPA during office hours on 8204 9934.