Probe starts into contaminated plume

The State Government had been looking into contamination at the site on Lot 51 Mason Road since 1982, when it was owned by Chemical Industries Kwinana, a company which had been disposing contaminated wastewater directly into the groundwater supply.

A significant diesel spill also took place on the site in the 1980s.

Since buying the site from CIK in 1985, herbicide and pesticide manufacturer Nufarm has spent decades and millions of dollars remediating the land and turning it into a hardstand facility to avoid future contamination.

But the plume, which is about 1700m from Cockburn Sound and has remained in a fairly stable position, still exists and is the subject of an ongoing study.

Aurora Environmental’s Noel Davies, consultant to Nufarm, told attendees at the previous Kwinana Communities and Industries Forum that the contaminants were mostly soluble salts.

While an on-site health assessment has indicated there are no risks to workers, Aurora is about to start investigating the offsite plume in greater detail.

Research done so far indicates that the plume may be biodegrading by itself, but Mr Davies said if the plume did reach Cockburn Sound it would be a ‘major concern’, although there was no evidence that suggested a ‘direct pathway’ to the Sound.

He said ‘less than desirable processes by CIK’ had led to the potential contamination.

‘The historical issue here is there used to be just a sump in the ground and all treated wastewater used to go into that sump,’ he said.

‘I’ve been aware of the plume for 40 years and in that time it hasn’t got further than 500 to 600 metres from the site.’

The research is expected to be completed by 2015.