Tonsley (formerly Clovelly Park) & Mitchell Park

It is the opinion of the auditor that the site is suitable for the proposed residential development, provided that numerous audit conditions are implemented. The audit conditions include requirements in relation to the development and environmental monitoring, including the ongoing monitoring of soil vapour and groundwater to be undertaken by Renewal SA, in accordance with a monitoring plan endorsed by the auditor. The ongoing monitoring continues to be undertaken by a consultant on behalf of Renewal SA.

It is the auditor’s opinion that whilst site contamination exists at areas 3 & 4, the sources of contamination were not identified within the audit area and contamination can be attributed to offsite sources.

Further assessment determined the nature and extent of groundwater contamination in the upper aquifer, which has extended off the Tonsley site in a northwesterly direction into Mitchell Park. The auditor’s opinion is that risk from vapour intrusion in areas off site are low and acceptable. The auditor also recommended that the EPA establish a groundwater prohibition area to prevent the use of the groundwater affected by site contamination. The audit statement (April 2020) is provided for further information.

For further information please visit the Renewal SA website.

In December 2019 the EPA agreed to a new voluntary proposal for a portion of the Tonsley site formerly defined as ‘section 17 – Plastics, Painting and Plating Shop’.  In accordance with the voluntary proposal a site contamination auditor has been engaged by Renewal SA for ‘Lot 34’ being a portion of the former section 17.

Detailed site investigations are being undertaken to determine the nature and extent of site contamination and to identify and assess any potential risk to human health and the environment.

The assessment of site contamination at the Tonsley site remains ongoing as the site is redeveloped.

2014 assessment

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.

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. 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 2014 fact sheet

• Audit statement, 17 April 2020
• 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