Clovelly Park-Mitchell Park
Renewal SA enters into a Voluntary Site Contamination Assessment Proposal
In May 2015 the EPA approved a Voluntary Site Contamination Assessment Proposal provided by Renewal SA, as owners of the former Mitsubishi Motors site in Clovelly Park.
As part of this agreement, Renewal SA has engaged specialist environmental consultants to assess the nature and extent of groundwater contamination onsite and to the west and north of the site in the residential areas. In June 2016, nine new groundwater wells were installed north of Alawoona Avenue, Mitchell Park.
Renewal SA has also engaged two site contamination auditors to oversee this work – one for the proposed residential area on site and the other for the assessment of the former industrial site and the impacts extending offsite. As South Australia’s environmental regulator, the EPA is overseeing Renewal SA’s completion of the agreed Voluntary Site Contamination Assessment Proposal, as part of the redevelopment of the former Mitsubishi site (now called the ‘Tonsley’ site).
For further information please visit the Renewal SA website.
The EPA completed a comprehensive environmental assessment program in December 2014, which detected the presence of trichloroethene (TCE) in soil vapour, soil and groundwater, coming from a former industrial site or sites.
In 2014, as a precautionary measure, 23 residents were offered relocation. This was due to the prediction of high levels of TCE vapour indoors. The EPA, on behalf of government, undertook further assessment of approximately 1,400 properties.
- 52 properties were deemed to be ‘safe’ with no TCE predicted in indoor air
- 25 properties fell within the detection to less than 2 µg/m3 TCE ‘safe’ range
- 15 properties fell within the 2–20 µg/m3 TCE ‘investigation’ range. ·
- 8 properties fell within the 20–<200 µg/m3 TCE ‘intervention’ range.
Frequently asked questions
How has the groundwater in the Clovelly Park area become contaminated?
The groundwater contamination has originated from at least three industrial properties in the Clovelly Park area. Past industrial use and disposal practices associated with the properties has caused the contamination. These practices are now understood to have contaminated the soils at the industrial properties and subsequently have leached (moved) down to the groundwater.
Over time, the contamination in the groundwater has moved naturally, further polluting the groundwater beneath the industrial properties and neighbouring residential properties.
What is the EPA doing to determine the extent of groundwater contamination?
The extent of the groundwater and soil vapour contamination has not yet been determined. More investigation is required in areas further south into Clovelly Park and west into Mitchell Park. This work is intended to determine the full area of the TCE contamination.
The EPA is in the process of engaging a specialist site contamination consultant to undertake the further groundwater, soil and soil vapour investigations in the Clovelly Park/Mitchell Park EPA Assessment Area.
How did the TCE become to be present as soil vapour in the Clovelly Park area?
The contaminant is trichloroethene (TCE) which is a chemical that was used widely in industrial and commercial activities. In the Clovelly Park area it was used for metal cleaning and degreasing. TCE is a volatile chemical meaning it readily evaporates and forms vapours. Previous activities undertaken at the industrial properties, including the storage and disposal activities that were considered acceptable at that time, has resulted in TCE being released to the environment.
Used TCE was historically poured out onto soil with the intention that it would evaporate and the dirty residue would be scraped up and disposed of.
It is now known that when liquids containing the chemical TCE, and related chlorinated hydrocarbons, are spilt or discarded onto the soil, they can migrate down through the soil and dissolve in the groundwater. The dissolved contaminants will typically move naturally with the groundwater in the natural direction of the groundwater flow.
Over a period of time, TCE and other chlorinated hydrocarbons can change to a gas phase. They will then migrate upwards through the soil as a gas or 'vapour'. The vapour that accumulates in the soil pore spaces is termed 'soil vapour'. The soil vapour can migrate further and result in vapour intrusion into buildings and other underground structures.
How long has the contamination been present?
The contamination is historical, probably entering soils and then groundwater during the 1960-80s. TCE was widely used in industrial activities, particularly for metal cleaning/degreasing. Loss to the environment generally occurred from storage and disposal activities that were considered acceptable at the time.
The EPA has been undertaking extensive research to identify the sources of contamination. This work includes the review of historic reports, historic records, historic aerial photographs, historic Certificates of Title, historic documents and the identification of past contaminating activities that have been undertaken at industrial/commercial properties in the Clovelly Park area.
Further information is required to determine the exact source of the soil vapour contamination that is causing vapour intrusion. The EPA has found multiple source locations that will form part of the further investigation work to be undertaken by the EPA.
What investigation work will the EPA be undertaking in the Clovelly Park/Mitchell Park EPA Assessment Area?
As more investigation is required to determine the full area of the TCE contamination, the EPA will be undertaking investigations in the southern areas of Clovelly Park and west into Mitchell Park. This investigation work will include the installation of groundwater investigation wells (bores), soil borehole testing to further identify soil source locations. This testing will assist the EPA in determining the source of the soil vapour, which is currently not known. A soil vapour screening assessment will also assist in the determination.
The EPA will be engaging a specialist site contamination consultant to undertake this work. A very comprehensive and complex drilling program to assess the extent of the groundwater and soil vapour contamination will be completed. The assessment work will commence during August 2014 and will be undertaken over a three to four month timeframe.
The EPA plans to complete the assessment work as quickly and thoroughly as possible. The EPA is committed to ensuring that all work is of a high quality and is scientifically reliable. The EPA welcomes questions or discussion about any aspect of this assessment work.
Where will the EPA be testing?
As more investigation is required to determine the full area of the TCE contamination, the EPA will be undertaking investigations in the southern areas of Clovelly Park and western areas of Mitchell Park.
This investigation work will include the installation of groundwater investigation wells (bores), and soil borehole testing to further identify soil source locations.
This work will be undertaken primarily on road verges and council reserves.
Will the EPA undertaking indoor air testing?
At this time, the EPA’s assessment work will be testing the groundwater and soil vapour (soils) predominantly along road verges and council reserves. Once this testing has been completed, the EPA will determine if any indoor air testing is needed.
What further investigation work is industry doing in the area?
As part of the ongoing program of investigation works being undertaken by Monroe Australia Pty Ltd (Monroe), a further round of groundwater testing will be undertaken by Monroe’s site contamination consultant URS Australia Pty Ltd (URS). URS will be testing groundwater monitoring wells in the Clovelly Park area over the last two weeks of July.
Monroe has continued to engage an independent site contamination auditor who is accredited by the EPA, for the purpose of completing a site contamination audit report for the Monroe property located along South Road, Clovelly Park. Once the groundwater testing has been completed, the results will be reported to the site contamination auditor for specialist review. At that time, a copy of the results will be provided to the EPA and SA Health.
The EPA will continue to provide residents and the community with updates of the work Monroe and other industry will be carrying out in the Clovelly Park area over the upcoming months.
What is trichloroethene (TCE)?
Trichloroethene, also known as trichloroethylene or TCE, is a colourless liquid chemical that is widely used in industrial activities, particularly for metal cleaning/degreasing. It was also used in production of products such as adhesives, lacquers, dyes, perfumes and soaps. Other historical uses include removing caffeine from coffee beans in the production of decaffeinated coffee, for dry cleaning and as an anaesthetic for surgery.
Chemicals that readily evaporate and form vapours are known as 'volatile chemicals'. These chemicals are normally associated with strong odours. Common examples that include volatile chemicals are petrol, kerosene, mineral turpentine (turps) and nail polish remover. TCE is a volatile chemical and it is now known to last in the environment for hundreds of years.
Liquid TCE has physical properties that cause it to move vertically downwards (sink) through soil and groundwater. The liquid TCE then sits at the bottom of the groundwater table and migrates naturally with groundwater over time. Sometimes this chemical can migrate over hundreds of metres. The TCE can also bind to soil particles and accumulate in holes and spaces in the soil profile. From its resting place in the soil and groundwater, the TCE slowly becomes volatile over time resulting in the TCE, as a vapour, returning to the surface.
What is the problem posed by 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 (vapour phase) and move through pore spaces in the soil to the ground surface.
Exposure can occur if the chemicals migrate through the soil pore spaces to the ground surface, and then find their way through crawl spaces, 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 who live or work in the building. The risk posed by these chemicals depends on many factors including concentration, exposure time per year, the number of years of exposure and age.
What is vapour intrusion?
Vapour intrusion is the movement of chemical vapours from contaminated soil and groundwater into nearby buildings. Vapours enter through openings in the building foundation or basement walls ─ such as cracks in the concrete slab, gaps around utility lines (power, gas, water, sewage), and sumps (for water collection). It is also possible for vapours to pass through concrete, which is naturally porous. Once inside the home or workplace, vapours may be inhaled. Sometimes these vapours can pose health risks to the occupants.
Risks will depend on the types of chemical vapours and their concentrations, how much time people spend in the building, and the building’s ventilation. Vapour concentrations will be higher indoors when windows and doors remain closed.
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, the EPA and SA Health have no concerns about the outdoor air quality in the area.
This has been confirmed by the results of previous outdoor air testing in the Clovelly Park area.
Am I or my family at risk from the soil vapour?
At this time the EPA does not have any information that can be used to assess a soil vapour risk for the homes south and west of the area recommended for relocation. The work planned needs to be undertaken to assess this risk.
Can I use bore (groundwater) water for any use?
The EPA and SA Health advise residents and property owners to not use bore water for any use until further notice.
For example, the bore water in the area should not be used for drinking, irrigation or any other uses until further notice is provided by the EPA.
If you are outside the Clovelly Park/Mitchell Park EPA Assessment 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.
For further information please see SA Health factsheet on borewater testing.
I have a groundwater bore on my property. Can I use the bore water for drinking water, to fill up the rainwater tank, to irrigate the garden, to water the lawn, to wash down the paths and driveway or to use as grey water in the house (eg toilet flushing)?
The EPA and SA Health advise residents and property owners to not use bore water (underground water) for any purpose until further notice.
If you live in the Clovelly Park/Mitchell Park EPA assessment area, the EPA advises you not to use your bore water for any use.
If you live outside the Clovelly Park/Mitchell Park EPA Assessment Area, it is recommended by the EPA and the SA Health that all groundwater (where use is not prohibited by the EPA) is tested prior to use.
For further information please see SA Health factsheet on borewater testing.
Is it safe to use my tap water, mains water or rainwater?
Yes. Tap water (provided by SA Water) and rainwater tanks are not affected.
I have a groundwater bore that has been tested in the past; can I continue to use it?
If you live in the Clovelly Park/Mitchell Park EPA Assessment Area, the EPA advises you not to use your bore water for any use.
If you live outside the Clovelly Park/Mitchell Park EPA Assessment Area, it is recommended by the EPA and SA Health that you continue to regularly test your bore prior to use.
For further information see SA Health factsheet on borewater testing.
Can the EPA check the depth and test the quality of my bore water?
The EPA does not undertake testing for this purpose. The EPA has asked private bore owners to advise the EPA if they have operational bores, and request that residents not use bore water (groundwater) for any purpose.
The EPA and SA Health recommend that all groundwater (outside of the Clovelly Park/Mitchell Park EPA Assessment Area) is tested prior to use.
For further information see SA Health factsheet on borewater testing.
How can contact with these chemical substances occur if they are in groundwater (bore water)?
Exposure or contact can occur through contact with skin, orally (through the mouth) or inhalation (through the nose or mouth). Examples of how this can occur include using contaminated groundwater for drinking or cooking, in showers, swimming pools, toilets, water for food producing animals such as chickens, and irrigation of lawns or gardens. The contaminated groundwater is approximately 16-18 metres below ground surface.
I would like some information on fruit trees and root depths of fruit trees that grow in areas where there is trichloroethene (TCE) groundwater contamination?
Most fruit trees have shallow root systems where the active root zone for water uptake is generally limited to the upper 0.5 to 1 metre of soil. Some plants, such as grape vines do extend their root systems down to the water table when rainfall is scarce.
SA Health has advised the EPA that:
[An] assessment of the available literature indicates that the likelihood is low, of fruits and vegetables grown in soil near contaminated groundwater, containing TCE and related compounds at levels that might represent a risk to health. Typically SA Health advises that in areas impacted by TCE contaminated groundwater, home grown vegetables are safe and do not pose an appreciable risk to residents who consume them, provided they are not watered with contaminated groundwater.
Has the community in the Clovelly Park/Mitchell Park EPA Assessment Area received correspondence from SA Health in the Clovelly Park area in the past?
During November 2008, SA Health advised residents of soil testing work that was being undertaken in localised areas of Clovelly Park and Mitchell Park. This was provided through a letter to local residents, following the identification of groundwater contamination found on the former Mitsubishi Motors Australia property.
SA Health also advised residents within a localised area of Clovelly Park and Mitchell Park not use groundwater for any purpose unless it was tested and deemed safe for its intended use.
Has the community been told about the groundwater and soil vapour contamination at Clovelly Park in the past?
During early 2009, the EPA and SA Health advised local residents of groundwater contamination that was identified by Mitsubishi Motors Australia Ltd at its former property. The EPA and SA Health undertook indoor air sampling at a number of properties within the Clovelly Park area during early 2009. Monroe Australia Pty Ltd has also been undertaking testing in the area.
Since September 2012, ongoing communication of the work that has been undertaken by Monroe Australia Pty Ltd has been provided to selected residents. Most recent communication and engagement by Monroe Australia was undertaken in December 2013. Copies of all letter communication, SA Health fact sheets, and EPA media releases are available on the Clovelly Park/Mitchell Park page.
Will the EPA provide further information to the community about the ongoing investigation work that will be undertaken in the Clovelly Park and Mitchell Park areas?
The EPA will be providing monthly updates on the progress of investigation work that is being undertaken within the Vapour Mitigation Area of Clovelly Park. The monthly updates will provide the community with updated information of the progress of the EPA’s investigation work of determining the extent of the groundwater and soil vapour plumes in Clovelly Park and Mitchell Park areas.
Over the coming weeks, the EPA will be holding open-house style community information sessions that will provide an opportunity to residents within the area and the wider community to have one-on-one discussions with officers of the EPA and SA Health. The EPA will invite residents to attend the open house discussion sessions as soon as the wider investigation area has been determined.
The EPA’s website provides additional information and is continually being updated as new information arises.
Are more relocations planned?
Currently, the EPA has no information that suggests that further precautionary relocations will be recommended. Relocation recommendations are extremely rare and only occur once there is sufficient data to support such an outcome. Please note that residents in the recommended precautionary relocation area were recently advised by SA Health that there is no immediate risk posed by the TCE in soil vapour.
Is there a soil/groundwater vapour issue associated with the contamination arising from contaminated groundwater?
As part of the EPA assessment process in the area, the risk of vapour entering homes and buildings will be investigated.
If I relocate and take my furniture with me, is there a risk to my health?
Soft furnishings will not absorb TCE indoor air at any level that could pose a health risk. It is safe to take soft furnishings to new homes.
In 2008, as a part of the due diligence process for the sale of its South Road, Clovelly Park (Tonsley) site, Mitsubishi Motors Australia Ltd (Mitsubishi) undertook groundwater testing at the southern boundary of the site. This testing indicated the presence of elevated concentrations of TCE (trichloroethene) in the groundwater and soil vapour. Mitsubishi voluntarily notified the EPA about these elevated concentrations.
The soil contamination in the Clovelly Park area immediately to the south of the former Mitsubishi site is likely to have occurred as a consequence of the historical disposal of a metal cleaning agent containing TCE. From the 1960s to the 1980s, the recommended method of disposal for such cleaning agents was to pour them onto the soil and allow them to evaporate. Groundwater contamination is thought to originate from at least three industrial properties in the Clovelly Park area.
Groundwater and soil assessments have been progressively undertaken in the Clovelly Park area south of the former Mitsubishi since 2008. The EPA, through its contractor Fyfe Pty Ltd conducted drilling and testing in the Clovelly Park and Mitchell Park assessment area. The assessment works enabled the EPA to better understand the groundwater conditions, the extent of soil and groundwater contamination and whether there are any issues associated with soil vapour in the wider area.
Mitchell Park validation assessment report
In March 2015, the EPA and its environmental consultant Fyfe Pty Ltd, commenced an assessment program to validate the results of the predicted TCE indoor air levels for some properties at the northern and southern ends of Woodland Road, Mitchell Park.
The Mitchell Park Validation Assessment Works Final Report (2 July 2015) shows the predicted levels of TCE in indoor air for these properties remain in the ‘safe’ indoor air response range as per the results of the December 2014 assessment report. This confirmed that there was no health risk to any occupants of properties along Woodland Road.
The highest predicted indoor air result measured 0.17 µg/m3 of TCE, similar to the December 2014 assessment results for Mitchell Park. An indoor air level of below 2 µg/m3 is considered safe.
Letters to residents
Renewal SA letters 2015–16
- 14 July 2016 (Phase 2 update)
- 15 June 2016 (Ash Avenue, Chestnut Court community consultation)
- 25 May 2016 (Phase 2 update)
- 2 March 2016 (Ash Avenue, Chestnut Court demolition works)
- 17 July 2015
EPA letters 2014–15
Monroe's letters 2012–15
- For the latest information please visit Renewal SA website
- Clovelly Park-Mitchell Park Environmental Management Project website
- Indoor air level response range for TCE in Clovelly Park
- SA Health website - trichloroethene (TCE)
- Submissions to Parliamentary and Board Committees
- Validation assessment results 2015 fact sheet
- Clovelly Park-Mitchell Park July 2014 fact sheet