The City of Mitcham entered into a Voluntary Site Contamination Assessment Proposal in September 2020 to undertake an environmental investigation associated with a former landfill on Port Lincoln Boulevard in Pasadena.
The environmental investigation involved the assessment of landfill gas and groundwater at, and close to, the former landfill site.
The site on Port Lincoln Boulevard in Pasadena was used as a landfill from the late 1950s to approximately 1969. The City of Mitcham was involved, along with others, in the disposal of general household waste at this site from 1959 to 1962.
Environmental investigations at the site have been ongoing since the mid 1990s, undertaken by a range of organisations, including the Environment Protection Authority of South Australia.
Environmental investigation work has been undertaken by an independent environmental consultant to better understand the nature and extent of potential environmental impacts which involved drilling wells and bores to sample groundwater and landfill gas.
Detailed Site Investigation Report August 2022
The environmental investigations associated with the 2020 Voluntary Site Contamination Assessment Proposal are complete and results have been reported upon in a Detailed Site Investigation Report.
This report has undergone Site Auditor and Environment Protection Authority of South Australia (EPA) review and the findings within it have been agreed and endorsed.
A Detailed Site Investigation report determines the impact of former land use activities on a site – in this particular case its historic use as a landfill – and is the main reporting outcome of the 2020 Voluntary Site Contamination Assessment Proposal. The Detailed Site Investigation report is available through the EPA Public Register.
A summary of the reporting outcomes is available here
No evidence of landfill gas (methane and carbon dioxide) movement into residential properties next to the historic landfill site was found and the risk of this occurring has been assessed as low. One property, built in part over the landfill, was found to be the exception and Council has been working closely with the residents.
Concentrations of other chemicals in soil, soil vapour and groundwater were found to be low and acceptable.
The report identified limited additional investigations are needed to further confirm these findings. The City of Mitcham has agreed to carry out these additional investigations.
The City of Mitcham has entered into a second Voluntary Site Contamination Assessment Proposal in November 2022 to continue the assessment of the nature and extent of landfill gas and groundwater at, and close to, the former landfill site.
Additional Investigation Work Begins December 2022
As part of the 2022 Voluntary Site Contamination assessment Proposal, five new gas bores will be installed at Lot 101 Port Lincoln Boulevard. around the edge of the former landfill and four new landfill gas bores will be installed on road verges in Quinton Court, Yorke Drive and Port Lincoln Boulevard to better understand background (naturally occurring) concentrations and gas movement.
The new landfill gas bores will be in place by mid-December 2022.
These bores will allow for additional investigations to further inform:
- Whether concentrations of chemicals in buried waste or soil vapour within the former landfill are above EPA guidelines for open space / recreational or residential land use.
- Whether landfill gas is present near the boundary of the underground waste and whether it is moving.
- Whether concentrations of chemicals in shallow and deep groundwater on and nearby the site are above EPA guidelines for protection of the environment.
Monitoring of gas concentrations and movement will be undertaken for a period of three (3) months following the installation of the new landfill gas bores.
We will share a summary of results and findings once available in the second quarter of 2023.
A Detailed Site Investigation addendum report for the landfill gas, soil, soil vapour and groundwater investigations will be developed and a summary of results and findings shared once available mid 2023.
A dedicated engagement team, from a local company called TSA, is continuing to work closely with property owners and residents to address any questions they have relating to the environmental investigation.
This team will be providing information to the community about the environmental investigation works and assist with the management of any potential inconvenience caused by this work in the community.
Previous Community Updates
Sampling of new and existing wells and bores and sampling and monitoring of landfill gas in selected enclosed spaces has been undertaken.
Information about the investigation and a summary of some of the environmental findings to date, particularly in relation to the landfill gas monitoring bores is available in our July 2021 Community Update.
Three new groundwater wells and seven new landfill gas bores have been successfully installed in locations at Quinton Court, in the shared laneway between Quinton Court and Thiselton Crescent and at the end of Yorke Drive. For more information download the Community Update April 2021.
New onsite and offsite groundwater wells and landfill gas bores at varying depths will be installed. Existing groundwater wells and landfill gas bores will be sampled.
Sampling of all groundwater wells and landfill gas bores will take place at different times of year to capture a range of climatic and soil moisture conditions.
In 2019, the EPA commissioned monitoring for landfill gas in and around properties near the southern boundary of the former landfill.
No unacceptable risks to human health or property were found as a result of the sampling and analysis work completed in 2018/19.
Further information about the earlier assessment work is available on the EPA's website.
Regular updates will be provided to the local community and on our website. Key members of the project team are available to answer questions. You can contact us via phone:
- Leslie Wapler, ProManage on 0428 063 924
- John Valentine, Senior Property & Facilities Advisor on 0412 469 855
- Matthew Romaine, Group Manager on 0429 218 708
The Audit Committee was presented information on the land management investigative process being undertaken by the City of Mitcham. The agenda and minutes are available below: