But despite the alterations, developer LandCorp says the ‘health risk is considered to be very low’.
The original plan was endorsed by the WAPC in July but had to be altered after lead was found beneath the surface of a lot on Bennett Avenue.
Fragments of asbestos, believed to have been dumped illegally recently, was found on the surface of the site.
The discovery meant a change to one of the sections previously identified for stormwater infiltration. The site’s original drainage reserves will be retained.
Another piece of land that had been zoned residential will now be reserved as civic public purpose.
LandCorp has told the City of Cockburn it would rather manage the contaminated soil onsite rather than opt for the alternative of excavating the tainted sections.
Managing it onsite would involve covering it with a geotextile material and a layer of clean fill.
LandCorp chief executive Frank Marra said the developer would follow regulations laid out by the Department of Environment and Regulation and the site would be safe.
‘Given that the lead material is in a solid form and is also located beneath the surface at depths between 0.5m and 6m, the health risk is considered to be very low,’ he said.
‘Asbestos-containing material, which is currently being removed, is limited to selected locations on the surface and is located well away from residential locations.’
A City officer’s report said that while it was unusual to keep contaminated soil on site, ‘it is acceptable in similar circumstances, both nationally and internationally’.
‘The contaminated material is largely lead which is not especially toxic and doesn’t leach to ground water,’ the report says.
Cockburn planning and development director Daniel Arndt was confident residents were not at risk.
‘The site is proposed to be remediated to a standard that will mitigate health concerns to the satisfaction of council and the State Government,’ he said.
‘There are no contaminants in any of the areas of public open space .
‘The City acknowledges that the removal of the contamination may pose potential health risks and that the remediation proposed by Landcorp would result in minimal impact for existing and future residents.’