Edwardstown-South Plympton (Hills)
Groundwater Prohibition Area
Groundwater in this area is contaminated and the EPA established a groundwater prohibition area 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.
Ground (bore) water contamination
Since 2009, the EPA has been overseeing an ongoing program of environmental assessment works at the former Hills Limited (Hills) vacant industrial site. This vacant site is bordered by Raglan Avenue, South Road and the rail line. These works have also extended into the adjacent residential area.
Site contamination audits, which are independent reviews of this work, have been carried out by 2 site contamination auditors accredited by the EPA under the Environment Protection Act 1993.
The auditors are satisfied with the extent of assessment and remediation that has been completed for mixed uses at this site, subject to various conditions.
Residents and property owners in Edwardstown–South Plympton area were first advised by the EPA in February 2011 not to use bore water (underground water) for any purpose until further notice to ensure that direct contact with contaminated groundwater does not occur. Water from mains and rainwater tanks are not affected by this issue.
The chemicals which have been found are fuels and industrial solvents, primarily tetrachloroethene (or perchloroethene, PCE) and some trichloroethene (TCE) which were widely used in the past as metal cleaners and degreasers. These chemicals have been found in groundwater at levels above the Australian Drinking Water Guideline values.
The area identified by the EPA where residents have been advised not to use groundwater while under investigation is bounded by Marion Road to the west, Oval Terrace and Nelson Street to the south, Railway Terrace to the east and Maxwell Avenue and Melville Street to the north.
To investigate whether there were any potential risks from vapour intrusion, the EPA undertook indoor air sampling in approximately 20 selected houses in the area. The then Department of Health (SA Health) considered the results indicated that concentrations of the chemical substances were typical of environmental chemicals expected to be found in urban homes, with the exception of tetrachloroethene, also known as perchloroethene (PCE). However SA Health advised that that the levels of PCE detected are below the appropriate health guideline value and, as such do not indicate a health risk. SA Health noted the point in time nature of indoor air testing was inadequate alone as a basis for a formal human health risk assessment.
Following the EPA’s request to progress with further assessment in order to protect the health of residents in the vicinity of the site, Hills engaged environmental consultants, URS, to undertake an offsite assessment program including groundwater, soil vapour and indoor air sampling. The results of this program have been reviewed by an independent EPA accredited site contamination auditor as part of the ongoing audit of the site contamination, which commenced in March 2011.
Hills, through their consultant, URS Pty Ltd, has progressively provided the EPA with groundwater notifications as a result of further testing to determine the full nature and extent of the contamination. The testing was completed by the consultant as part of the progression of the site contamination audit.
The EPA is using the results of the groundwater testing to define a boundary for a Groundwater Prohibition Area (GPA), in accordance with the Environment Protection Act 1993. When established, the GPA will formally restrict access to groundwater in an identified area and depth for any purpose. This is the most effective way to protect the health and safety of the community from groundwater contamination.
The EPA will consider all appropriate information, including assessments that have been reviewed by the site contamination auditor to determine the extent of the GPA. The EPA will keep the local community informed of the progress of the establishment of a GPA.
- December 2017 Determination report
- March 2016 Audit report area 3 – Report | Annex A | Annex B | Annexes C–K available upon request due to file size | Audit Statement
- March 2016 Audit report area 2 – Report | Annex A | Annex B | Annexes C–K available upon request due to file size | Audit Statement
- February 2016 Audit report area 1 – Part 1 | Part 2 | Figures | Audit statement
- Ground monitoring & management plan
- Construction environmental management plan – Part 1 | Part 2
- Site management plan – Part 1 | Part 2 | Part 3 | Part 4
Letters to residents
- 17 March 2016
- 23 March 2012
- 19 May 2011
- EPA letter to The Advertiser, 6 March 2011r
- 3 March 2011: Test results received today by the EPA show that chemicals associated with the former Hills Industries site contamination (TCE, PCE, DCE and vinyl chloride) were not detected in either the council or school bores.
- 24 February 2011
- 23 February 2011
Frequently asked questions
What is a groundwater prohibition area?
A groundwater prohibition area is established under section 103S of the Environment Protection Act 1993. This section of the Act allows the EPA to prohibit or restrict the taking and groundwater if it may be harmful to human health or safety.
The community then has the responsibility not to use the groundwater for their own health and safety.
Why does this have to be recorded on my Certificate of Title?
It is important that all current and future owners are made aware of the prohibition. The EPA cannot notate on the Certificate of Title the existence of the water prohibition area. In order to ensure that future purchasers of properties within a groundwater prohibition area are made aware of the prohibition, a notification of an interest held by the EPA will be made on the Form 1 statement. This is a document that is required to be provided to a prospective buyer before settlement under section 7 of the Land and Business (Sale and Conveyancing) Act 1994.
How will this information be made available to people interested in my land or potential purchasers of the land?
The EPA will flag its interest in the certificates of title within the GPA with the Land Titles Office. Notice will then be given to any interested parties on the Form 1 statement (which forms part of the contract of sale) via Section 7 of the Land and Business (Sale and Conveyancing) Act 1994 where it is shown as a prescribed encumbrance. For further information please read the Section 7 information sheet.
What if I want to build a basement?
If you are intending to build on land within the former Hills site and a specific adjacent area within the residential area west of the site, as far as being practicable and enforceable, any new habitable basements greater than 2 m in depth in existing or future houses should incorporate a soil vapour mitigation (removal) system. It must comprise a proprietary membrane and passive venting layer, designed and installed by a qualified and experienced person(s), so that soil vapours can be safely ventilated to the atmosphere.
The residential area to which these specific controls apply is identified by the auditor in Figure 19 of the audit report, and a link will be provided when the audit report is made publically available in April.
Will bore water contamination affect my property value?
The presence of groundwater contamination means that bore water has not been able to be used from shallow aquifers at properties in the affected area, in accordance with SA Health and EPA advice since 2011. The EPA’s experience in managing other similar incidents of contamination is that property values were not affected.
The Groundwater Prohibition Area 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.
What was the involvement of URS?
URS are experienced site contamination consultants who were engaged by Hills Holdings to progress with assessments in the residential area. URS work included investigations aimed at assessing the presence and use of underground building structures and householder bore water access in a limited area within the EPA investigation area.
What were the results of indoor air testing undertaken in April 2011?
Indoor air sampling conducted by the EPA was carried out in 20 homes in the area in April 2011 at locations where the groundwater contamination was knownto have been most concentrated. The results of this sampling were assessed by both the EPA and SA Health.
The results indicated that the concentration of the chemical substances in the indoor air data was typical of environmental chemicals expected to be found in urban homes, with the exception of perchlorethylene (PCE). However, SA Health has advised that the levels of PCE detected at that time were below the appropriate health guideline value and, as such, do not indicate a risk to health.
In summary, testing was conducted for certain solvents and industrial chemicals, including trichloroethene (TCE) and perchloroethene (PCE), benzene xylenes ethyl-benzene and toluene (BTEX) and other related chemical substances. These chemicals are commonly used in manufacturing processes and/or in fuels.
How did the EPA become aware of the contamination?
In mid-February 2011 the EPA was provided an expanded notification of contamination in shallow groundwater under residential properties adjacent to the former Hills Industries site at Edwardstown. The information identified a new area of contamination which was likely to affect domestic bore water users in the vicinity. This followed ongoing work by the former and current owners as part of exploring redevelopment of the site.
Site contamination is normally initially identified at the source site and investigated in stages until the nature and the extent of the contamination is fully understood.
Elevated levels of chlorinated hydrocarbons, primarily by PCE (perchloroethene) but also including TCE (trichloroethene), DCE (dichloroethene) and VC (vinyl chloride), were encountered in soil and groundwater beneath the former metal cleaning facility at the site and in groundwater wells adjacent to the site.
Hills Industries and Colonial First State (now Vicinity Centres), through their consultant, have progressively provided the EPA with further notifications and updates of the site contamination status, including offsite migration of chemical substances, as a result of staged soil, groundwater and soil vapour assessment.
What are PCE, TCE, DCE and VC?
PCE (perchloroethene) and TCE (trichloroethene) are common industrial solvents and were used widely as degreasers and metal cleaners. DCE (dichloroethene) and VC (vinyl chloride) are generally present as the result of the degradation and breakdown of TCE.
For more information on the chemicals of concern, please refer to the fact sheet, Chlorinated solvents in groundwater, from SA Health.
How long has the contamination been present?
The contamination is historical in nature and arose from practices that were considered acceptable at the time. It is likely that the contamination was caused progressively from commencement of operations at the Hills site (circa 1945) and that these practices were phased out over time as environmental practices improved.
Historically, it was 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. Loss of containment was not considered significant.
Can I use the bore water?
The bore water in the area should also not be used for drinking, irrigation or any other domestic uses until further notice. The EPA will keep the community informed of the EPA’s progress in establishing a groundwater prohibition area under section 103S of the Environment Protection Act 1993.
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 area, 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)?
Contact with these chemical substances does not occur from normal tap water, which is plumbed to our house. Exposure occurs through using contaminated groundwater, if you have a groundwater bore in your garden and you pump the water for use to the house 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.
How many bores are present in the area of concern?
There are 33 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 are also present.
Is the water in the Forbes Primary School bore safe to use?
The EPA collected samples from the school's bore which were sent to a NATA (National Association of Testing Authorities) registered analytical laboratory. The results show the water to be free of the contaminants associated with the former Hills Industries site.
The contamination had been found in relatively shallow groundwater within the Edwardstown−South Plympton area. The water available in the school bore is sourced from a much deeper aquifer.
What is the problem posed by PCE, TCE and its breakdown products (DCE and vinyl chloride)?
The chemical substances found to be present in groundwater also have the potential to change from liquid to gas (volatilise) and move through pore spaces in the soil to the ground surface. It is then possible for the chemicals in gas form to further migrate and build up in confined spaces such as cellars and houses. The risk posed by these chemicals in homes would be through long-term exposure. Further investigations are being undertaken to confirm the potential for vapour intrusion to indoor air and, once received, the results of this investigation will be made publicly available.
Whether there is a problem will depend upon whether the chemicals are present, and if so, at what level and how many humans are exposed to the chemicals.
How did these chemical substances get into the air, soil and groundwater in the residential area?
PCE, TCE and its breakdown products (DCE and VC) 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 or moved directly as vapours from the source or became present through breakdown chemical reactions.
Liquid chlorinated hydrocarbons like TCE and PCE 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. Hydrocarbon vapour will move through soils via the path of least resistance, for example, through cracks, fissures or loose packing around pipes and drains.
Why was it necessary to sample the soil vapour at some locations?
The proposed further investigations by the consultant, URS were aimed at assessing the presence and use of basements and access of groundwater bores in an area known to be associated with the most concentrated part of the contaminant plume. Monitoring of groundwater bores over time to confirm groundwater contaminant stability and testing for soil vapour at shallow depths assisted with resolving uncertainties in the risk assessment.
The proposed further investigations assessed basements and access of groundwater bores in an area known to be the most contaminated part of the plume.
How was the indoor air sampling in houses undertaken?
Indoor air quality was tested using special steel canisters that draw in a known quantity of air over a 24-hour period. The canisters were then sent to an accredited laboratory and the air trapped inside them was analysed.
The canister sampling technique was chosen because it is very sensitive in detecting chemicals in the air and is very accurate, while causing little noise and disturbance to households.
Indoor air quality is also tested by using Radiello™ air samples that collect air through a tube. These air samplers were left in the home for up to two weeks to collect a sufficient sample and then sent to an accredited laboratory to be analysed.
The Radiello™ air sampling technique was used because it is very sensitive in detecting a different set of chemicals (VCs) and samples are collected from different locations in houses, including living and sleeping areas.
As part of the sampling program, the outdoor (ambient) air was also tested in the area, so that it could be compared with the air inside the houses.
Is it safe to breathe the outdoor air in the area?
As these chemicals are likely to be emitted at a very low rate from the soils and quickly dispersed in the outdoor air, EPA and SA Health had no concerns about the outdoor air quality in the area.
This has been confirmed by the results of outdoor air testing.
How can contact with TCE, PCE and the other related chemicals occur if they are present in the air spaces within the soil?
Exposure can 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.
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).
Are we exposed to TCE, PCE and the other related chemicals in the community?
Exposures to these chemicals may occur in the general community, for example, vinyl chloride (VC) is found in tobacco smoke while TCE can be found in some household products such as typewriter correction fluid and paint or spot removers.
DCE exposure can result from use of perfumes, lacquers and some plastics (eg thermoplastics). These types of exposures are referred to as ‘background exposures’. As exposures to chemicals occur from many sources in our everyday life, it is important that when there is a chance of exposure occurring that can be reduced or eliminated, action is taken.
It needs to be recognised that exposure to any one chemical often occurs from many sources to varying degrees and it is important to reduce total exposures to the lowest amount possible. This is to ensure total exposure levels are below those that may produce effects on health.
Are home grown vegetables safe to eat?
Contaminated groundwater generally does not contaminate the soil above it. Provided you are not watering your home grown vegetables with contaminated bore water, they are safe to consume. Most of the time roots don’t go down as far as the groundwater, but even in instances where they do – such as grape vines in times of drought – there is no evidence of fruit having absorbed the chemicals of concern.