Over the next few weeks some homes in the immediate vicinity of the Johnson's site will be directly invited to take part in indoor air quality monitoring.
This involves placing small monitoring devices inside key rooms and possibly under floors, as well as carrying out a brief visual inspection of existing ventilation and flooring at the property.
These tests do not require any drilling and will cause minimal disruption.
The chemicals involved were commonly used in dry cleaning, which was the main activity at the former Johnson’s factory. Over time, small amounts of these chemicals entered the ground.
In certain conditions, they can turn into solvent vapour (gas) and move up through the soil and into the air.
Exposure mainly occurs through breathing in these solvent vapours over time. Any health effects depend on how much exposure occurs and how long it lasts.
There is some evidence that health can be affected by these chemicals, however at low levels most people would not experience any impact on their health.
The purpose of these works is to identify, prevent and reduce the risk of any potential health impacts now or in the future.
Once testing is complete samples will be analysed and results will be shared with residents soon as possible.
If necessary further steps may include additional testing or practical measures to reduce potential exposure.
As part of plans to redevelop the site around 2012–2013, testing of ground conditions identified contamination associated with its previous uses. A remediation strategy was subsequently developed, and extensive works were undertaken, including the removal and treatment of solvents.
Although significant quantities of contamination were removed and treated, ongoing monitoring indicated that some contamination remained. As a result, redevelopment proposals were put on hold.
At that time, the developer’s consultants did not raise any specific concerns related to contamination potentially affecting neighbouring properties.
Since the initial remediation works, the site has changed ownership several times, and redevelopment recommenced. As part of this process, a review of the previous remediation and ground conditions was undertaken. This identified the need for further monitoring to inform any additional remediation requirements.
Subsequent testing and monitoring confirmed the presence of residual solvent contamination and that it has spread slightly beyond the original borders of the site.
Consultants therefore recommended undertaking indoor air quality monitoring within neighbouring properties to ensure that local residents are not exposed to unacceptable levels of vapours.