South-Eastern Edwardstown

The EPA undertook environmental assessment of soil vapour and groundwater contamination in South-Eastern Edwardstown between 2015 and 2020. Learn more about the previous stages of assessment through the South-Eastern Edwardstown Storymap.

Information collected from the adjacent Melrose Park EPA assessment area in September 2023 identified the need for further assessment of deeper groundwater in the South-Eastern Edwardstown area.

In May 2024, the EPA installed some additional groundwater monitoring wells to assess whether previously identified chlorinated hydrocarbon (CHC) contamination is also present in the deeper groundwater.

This assessment found CHC contamination in the deeper groundwater at several of the monitoring wells, with trichloroethene (TCE) detected at concentrations above the drinking water guideline.

Based on the deeper groundwater being contaminated by TCE, the current Edwardstown and surrounding suburbs groundwater prohibition area (GPA) will need to be extended. The EPA has advised property owners and residents with registered wells intersecting this deeper groundwater that they should not use the groundwater for any purpose.

Further assessment is required to determine how far the boundaries of the GPA should be extended. More groundwater wells will need to be installed and sampled, with work on site expected to commence in 2025.

The Stage 7 Environmental Assessment report (September 2024) is available in the Reports section below, along with copies of reports from all previous stages of assessment.

Groundwater Prohibition Area

Groundwater in this area is contaminated and the EPA established a GPA on 9 January 2018. A maximum fine of $8,000 may be issued if groundwater is extracted from the 1^st (0–8 m below ground level), 2^nd (0–15 m) and 3^rd (0–26 m) Quaternary aquifers in certain parts of this area (please see map). Deeper uncontaminated aquifers are exempt from this prohibition. Please visit Engage EPA for further information.

Previous assessment

The EPA has been assessing soil vapour in South-Eastern Edwardstown for historically used chemicals including TCE, since 2015.

An interactive journey about how the EPA used staged investigations to understand the nature and extent of contamination and what risks that contamination posed is now available through the South-Eastern Edwardstown Storymap.

Through text, photographs and map coverages, readers can navigate and interrogate information using their preferred device, helping to make the science of site assessment more accessible.

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Seasonal sampling undertaken in June 2020 was used to update a computer model, predicting whether TCE could enter residential indoor air. Concentrations of TCE and soil moisture conditions reported in June 2020 were comparable to previous stages of assessment.

The EPA confirmed that no properties in the assessment area were at risk of contaminated vapour entering indoor air at ground level or above. The EPA undertook basement surveys in 2015 and 2020 to ensure that residents with basements are also safe from the potential for vapour intrusion.

Background

TCE is an industrial chemical used widely as a metal cleaner and degreaser. In the past, TCE was used in many applications including electroplating, cleaning metal, dry cleaning, decaffeination of coffee and as an anaesthetic used in hospitals.

The purpose of this assessment program is to understand the nature and extent of groundwater and soil vapour contamination as a result of former industrial activities at two properties on Arabrie and Erudina Avenues, Edwardstown. These works have and continue to be managed by the EPA.

The soil vapour testing assists in understanding whether any contamination is moving through the soil in vapour form. Preliminary data found trichloroethene (TCE) and tetrachloroethene (PCE) in groundwater and soil vapour at several locations within the assessment area.

The human health risk assessment from 30 June 2016 found that all properties in the assessment area are considered to be safe, with predicted concentrations below 2 µg/m³ of TCE for indoor air.

In January 2017, the EPA undertook a 4th stage of work in the area. An additional 10 groundwater bores and 14 soil vapour bores were installed to delineate the lateral extent of TCE contamination. Sampling activities were carried out at new and existing locations to monitor the soil vapour for seasonal variation.

It has identified 3 potential source sites in the eastern part of the assessment area. The previous report, completed in May 2017, did not predict any vapour intrusion risks to residential properties and this remains unchanged and is consistent with all previous work.

The human health risk has been updated and all properties are considered to be safe from soil vapour intrusion, with predicted indoor air concentrations of TCE below 2 μg/m³. The EPA is now repeating a basement survey, previously undertaken in 2015, to ensure that residents with basements are also safe from the potential for vapour intrusion.

Community updates

Maps

Fact sheets

Reports

Stage 7 assessment report, September 2024
Assessment of South-Eastern Edwardstown – summary and closure report
11 July 2020, Soil vapour monitoring and updated health assessment
9 January 2018, Edwardstown GPA, Government Gazette, pg 18
December 2017 | Determination report | Report | Appendix A-F | Appendix G-H | Appendix I | Appendix J-L | Appendix M-P | Appendix Q-T
September 2017 | Report
May 2017 | Report | Appendix A.1 (Maps) | Appendix A.2 (Maps) | Appendix B–E (tables etc) | Appendix F–H | Appendix I–L | Appendix M–T
June 2016 | Maps | Report & App A&B | App C to G | App H to L | App M to T
March 2016 | Report | Appendices A–H | Appendix I | Appendices J–U
July 2015 | Report | Appendices A–F | Appendices G–L | Appendices M–S

Media releases