EPA assessment area
The EPA is undertaking environmental assessment work in Thebarton, where groundwater contaminated with trichloroethene (TCE) has been found in the vicinity of a former metal processing site on George Street. This is part of an ongoing ‘orphan site’ program, where the original polluter is not able to carry out the work and the site has been prioritised based on the potential for a risk to health.
The groundwater contamination is believed to be associated with past industrial practices that used a chemical trichloroethene (TCE). This is likely to have occurred as a result of historical chemical disposal and handling that was considered appropriate many decades ago but is no longer acceptable by today’s standards.
The risk of vapour from groundwater entering into residential indoor air has been assessed, with computer modelling predicting the majority of residential properties in the area to be safe.
During the first stage of groundwater and soil vapour assessment, the extent of the groundwater contamination was largely determined. Further work is required to find the boundary of the contamination in the north-western portion of the assessment area.
The Environment Protection Authority (EPA) has been assessing groundwater and soil vapour in Thebarton for historically used chemicals including trichloroethene (TCE), since May 2017.
It has long been understood that volatile chemicals can be transported in groundwater. More recently it has been discovered that they can also be found in the air spaces between soil particles as vapour.
The EPA conducted indoor air sampling in a number of properties within the Thebarton assessment area to identify whether any TCE vapours from the contaminated groundwater had entered their homes.
Nine of these properties measured no TCE in indoor air and are considered safe. Six of the properties measured within the 'Intervention' category of the indoor air level response range overleaf, and the EPA and Renewal SA are now working with these residents to design solutions that will reduce the TCE vapour to safe levels.
Mitigation systems have successfully been installed in homes in other areas of Adelaide with TCE vapour.