Clovelly Park-Mitchell Park (including Tonsley)

In February 2018 consultants engaged by Renewal SA undertook the first soil vapour and groundwater monitoring event since the completion of the audit report. Due to some increases in soil vapour concentrations an additional monitoring event was undertaken in April 2018. The results indicate an increasing trend in soil vapour concentrations, which promoted the revision of the vapour intrusion risk assessment for the residential audit area. 

The auditor has reviewed the monitoring results and the revised risk assessment, and considers that while the vapour intrusion risks have increased, the risks remain acceptable.  Further assessment was recommended and undertaken by Renewal SA in July 2018.

The EPA was then notified in July 2018 that a site contamination auditor has been engaged  in relation to areas on the wider Tonsley site considered to be a source of site contamination.

Inferred source areas 3 and 4

Another auditor was engaged in relation to southern portions of the former Mitsubishi Motors site, regarding assessment onsite and groundwater contamination extending offsite.

In 2016 the assessment of groundwater determined that the groundwater contamination had extended off the Tonsley site in a northwesterly direction. Additional soil vapour investigations and subsequent risk assessment did not identify a health risk to residents in houses with a slab on ground or crawl space.

In August 2018, Renewal SA wrote to approximately 3,500 properties within Clovelly Park, Mitchell Park and Marion. The letter advised the residents of the latest groundwater and soil vapour investigations undertaken during November 2017 and April 2018, which have confirmed similar results as previously identified. Residents were also reminded not to use bore water for any purpose, however mains water and water from rain water tanks are not affected.

The assessment and community engagement has been undertaken in accordance with the agreed timeframes of the VSCAP.

The interim audit advice prepared by the auditor is to be submitted to the EPA in November 2018.

As South Australia’s environmental regulator, the EPA is overseeing Renewal SA’s completion of the agreed voluntary site contamination assessment proposal.

For further information please visit the Renewal SA website.

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.

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).

Results

Please visit the Renewal SA website for the latest testing results.

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.

Assessment results

In summary:

• 1,352 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.

As the owner of the majority of properties affected by levels of TCE over 2 µg/m³, Housing SA made the decision to offer relocation to existing tenants and demolished many of these homes (shown above). Renewal SA has been engaging with the remaining residents to seek ideas on temporary plans for redevelopment of this open space for community use.

• Tonsley fact sheet, 6 March 2018
• Section 7 of the Land and Business (Sales and Conveyancing) Act 1994 and the role of the EPA
• Indoor air level response range for TCE in Clovelly Park
• SA Health: trichloroethene (TCE)
• Validation assessment results 2015 fact sheet
• Clovelly Park-Mitchell Park July 2014 fact sheet

• Audit statement, 7 December 2017
• Renewal SA Clovelly Park Community Open Space Engagement Report, March 2016
• Mitchell Park validation assessment works final report, July 2015
• Clovelly Park-Mitchell Park environmental assessment 2014 report summary
• Submissions to Parliamentary and Board Committees, 2014

Renewal SA letters

• January 2019
• August 2018
• 1 December 2016
• 8 August 2016
• 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

• 15 July 2015
• 8 May 2015
• 19 March 2015
• 12 March 2015
• 22 August 2014
• 17 July 2014

Monroe's letters 2012–15

• 14 October 2015
• 17 December 2013
• 16 October 2013
• 10 April 2013
• 17 January 2013
• 12 December 2012
• 5 September 2012

• Audit area, 7 July 2017
• TCE impacts in groundwater, 7 July 2017
• Clovelly Park predicted indoor air concentrations of TCE

• 17 July 2015
• 22 August 2014
• 17 July 2014
• 2 July 2014
• 12 April 2013
• 18 January 2013
• 13 December 2012
• 6 September 2012
• 20 January 2009 (SA Health)

Tonsley Village residential area

What information related to land quality is being given to buyers in the Tonsley Village?

Consumers purchasing property in South Australia are protected by the Land and Business (Sale and Conveyancing) Act 1994 (LSBC Act) and the Land and Business (Sale and Conveyancing) Regulations 2010. Sections 7 and 8 of the Act specify that a statement of government interests – on the required form (Form 1 or 2) – is to be provided by a vendor or their agent to a prospective buyer before settlement of land or a small business.

The EPA has a statutory obligation under the LBSC Act to provide information relating to environment protection on the Form 1. The EPA is required to respond to questions relating to both current and historical information and specifically about whether the land is subject to an audit report.

In relation to the Tonsley Village there are numerous questions on the Form 1 that the EPA is required to respond to, this will include identifying that a site contamination audit report has been completed for the Tonsley Village.  The site contamination audit report dated 7 December 2017, is the most current information prepared for the Tonsley Village. To make an enquiry, email the Section 7 team quoting the current Certificate of Title you wish to search.

Call the EPA on (08) 8204 2026 for further information or see the see the Information Sheet: Section 7, Land and Business (Sale and Conveyancing) Act 1994 and the role of the EPA.

What reports on land quality of the Tonsley Village are available?

The site contamination auditor (auditor) engaged by Renewal SA has completed the site contamination audit report or the residential area known as the Tonsley Village. The EPA has undertaken an administrative review and has accepted the audit report.

The site contamination audit statement, which is a summary of the audit outcomes and findings and is available on the EPA website. A full copy of the audit report is available upon enquiry to the EPA Public Register.

Any person can make a Section 7 enquiry by providing the EPA with a current Certificate of Title.

To make an enquiry, email the Section 7 team quoting the current Certificate of Title you wish to search. Call the EPA on (08) 8204 2026 for further information or refer to the Information Sheet: Section 7, Land and Business (Sale and Conveyancing) Act 1994 and the role of the EPA.

What is the role of the site contamination auditor?

The role of the auditor is to independently and objectively review and examine the accuracy and completeness of the assessment and/or remediation carried out by others. The outcome of this is a site contamination audit report prepared in accordance with the requirements of the Environment Protection Act 1993 and other relevant EPA guidelines. Further information on the site contamination audit system is available on the EPA website or by contacting us via any of the details below.

In relation to Tonsley Village, one of the purposes of the site contamination audit was to determine if the portion of the former Mitsubishi Motors facility (industrial land) was suitable to be redeveloped for a sensitive residential use.

The auditor has stated that the site is suitable for restricted residential use provided that no below ground structures (basements, cellars, carparks, etc) are constructed and provided that multiple conditions relating to development, environmental monitoring and site remediation and management are implemented. The auditor outlines in the audit report who is responsible for implementing the audit conditions.

A condition in relation to environmental monitoring requires Renewal SA to undertake the ongoing monitoring of soil vapour and groundwater in accordance with the Environmental Monitoring Plan – Tonsley SANZ endorsed by the auditor.

The auditor has stated that based on the condition of groundwater at the time of audit completion, and provided groundwater is not extracted for use, these impacts are not considered to present a risk to human health.

However, it is the auditor’s opinion that the ongoing monitoring is required to ensure that groundwater and soil vapour concentrations do not increase to unacceptable levels in the future. Please see the audit statement under ‘Reports’ above for further information.

Please see the Audit Statement (available on the EPA website under ‘Reports’ or by contacting us on the details at the end of this document) for further information.

What remediation remains necessary?

The auditor has outlined in the audit report what remediation is or remains necessary at the completion of the audit. The auditor has stated that various remediation activities remain necessary to prevent migration of soil vapour from outside the residential audit site and to ensure that vapour intrusion risk remains acceptable.

The remediation that remains necessary includes the construction of air tight bulkheads within some service trenches and geotechnical improvement of soils within specific areas of the residential area. The conditions relating to remediation are documented in the audit statement. There are also restrictions on the construction of sub-floor structures.

In the future, what happens if the soil vapour and groundwater monitoring identifies a change in concentration of chemicals that may be unacceptable?

The environmental monitoring plan, endorsed by the auditor, includes trigger concentration levels for soil vapour and groundwater. If chemical concentrations increase and the trigger levels are reached, then the monitoring plan includes contingency measures regarding what action should be taken. The contingency measures outline the remediation options for groundwater and soil vapour contamination. Renewal SA is responsible for implementing the monitoring plan and any contingency measures that may need to be implemented.

How has the groundwater in the Clovelly Park area become contaminated?

The groundwater contamination has originated from at least 2 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 moved down to the groundwater.

Over time, the contamination in the groundwater has moved naturally in a northwesterly direction, further polluting the groundwater beneath the industrial properties and neighbouring residential properties.

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 undertaken or required 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. In addition, drilling and analysis of soil, soil vapour and groundwater have occurred.

What are the chemicals of concern?

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.

Can I use bore (groundwater) water for any use?

Work to date has confirmed that the groundwater (bore water) in this assessment area is contaminated and should not be used for any purpose. Mains water and water from 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.

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. 

Since May 2015, Renewal SA as owners of the former Mitsubishi Motors site, has been undertaking the assessment of soil vapour and groundwater contamination in Clovelly Park, Mitchell Park and Marion (for a map of their current assessment area, please see the latest letter from Renewal SA in the ‘letters’ section above). Bore owners within the Renewal SA investigation area have been advised not to use the bore water (groundwater).

The EPA recommends that all bore owners outside of the Renewal SA Assessment Area – Clovelly Park, Mitchell Park and Marion – have groundwater tested prior to use. 

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.

Historical FAQs

Clovelly Park-Mitchell Park environmental assessment results, 3 December 2014

Housing SA: Residents frequently asked questions, 7 July 2014

Please visit the Renewal SA website.

For further information on health-related queries, please contact SA Health on 8226 7100.

For site contamination related enquiries, please contact the EPA on 1800 729 175 or email.