EPA orphaned site assessment for South-Eastern Edwardstown

‘Orphaned’ site contamination is a term used to describe a situation where the original polluter no longer exists, cannot be found or identified, or is unable to carry out or pay the costs of the assessment or remediation of contamination that is required.

The EPA commenced environmental assessment in South-Eastern Edwardstown in April 2015, following non-compliance with a joint site contamination assessment order (SCAO) for 2 former metal processing source sites of contamination on Erudina and Arabrie Avenues (the focus sites) in Edwardstown.

Between April 2015 and July 2020 the EPA commissioned multiple stages of assessment to determine the nature and extent of both groundwater and soil vapour contamination, predominantly trichloroethene (TCE) and other related chlorinated hydrocarbons (CHC), along with assessing the risk to residential properties from vapour intrusion.

Approximately 45 groundwater monitoring wells and 70 soil vapour bores were installed across the assessment area. The total cost of assessment was $832,707.

The Stage 4B assessment was completed in June 2017. Drilling was undertaken using a MiHPT in an attempt to pinpoint potential additional source locations. While CHC contamination was well characterised at numerous locations, it was reported that several plume areas and multiple source zones exist within the assessment area, and no specific new sources were identified.

Under section 103S of the Environment Protection Act 1993, the EPA may prohibit or restrict the taking of groundwater to prevent actual or potential harm to human health or safety, by establishing a groundwater prohibition area (GPA).

In April 2017, the EPA determined that groundwater in shallow aquifers in Edwardstown and surrounding areas had been significantly contaminated with chemicals arising from historical industrial practices within Edwardstown and Melrose Park (including the entire South-Eastern Edwardstown Assessment Area).

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.

In summary, the EPA assessment and remediation goals are considered complete, and risk to human health managed through the establishment of the GPA in 2018.

If any regulation of site contamination is required for the source sites or if the EPA is advised of any conditions that may change the risk profile, it will undertake further regulation and/or assessment in accordance with the  Regulatory and Orphan Site Management Framework . A copy of each of the assessment reports detailing each stage of assessment is available on the   EPA website .

The EPA established a community working group in November 2015 in South-Eastern Edwardstown. Meetings were held from 2015 to August 2016 for information sharing while the intial soil vapour assessment was underway. Meetings ceased when all indoor air levels measured and predicted fell into the ‘safe’ category of the  indoor air level response range (TCE) .

Regular updates on the EPA assessment continued for the duration of the project. Further details can be found at  Edwardstown and surrounding areas | Engage EPA 

If your property has a basement, please contact the EPA. This is to ensure that residents with basements remain safe from the potential of vapour intrusion.

For all enquiries, please contact the EPA on (08) 8124 4216 or  email .

The EPA acknowledges our First Nations peoples as the Traditional Owners of the land on which we live and work, and we pay our respects to their Elders past, present and emerging. We extend that respect to all Aboriginal and Torres Strait Islanders across Australia and acknowledge their deep and ongoing spiritual connection to Sea and Country.