INDUSTRIAL pollution has been identified as the cause of recent contamination in Cabramatta Creek.
Cabramatta Creek runs through the Elouera Bushland Reserve in west Liverpool, feeding into the Chipping Norton Lakes and joining with the Georges River.
Sydney Water investigators and Liverpool council officers collected samples of the contaminated water for analysis.
Inspections were also carried out at industrial complexes that drain into the catchment area.
A council report on the investigation traced the pollution to a factory unit operating upstream from the affected site.
"Steps were taken to remediate the immediate area around the factory and to provide bunding to the work areas within the factory to prevent future escapes of product into the stormwater system," the report stated.
"While we believe it may have been the same material that was found in Maxwell Creek, we are not able to definitively make that claim."
Maxwells Creek is also within the Georges River catchment and the Liverpool District sub-catchment.
The three-kilometre long creek starts in Prestons and flows north to link up with Cabramatta Creek.
Liverpool councillor Peter Harle asked council officers to explore practical, cost effective steps to ensure that future industrial pollution could be traced with certainty.
He was advised there were no practical ways in which the council could ensure the traceability of future possible contaminants as they were sometimes caused by illegal dumping into watercourses or onto land adjacent to watercourses.
The council will look at the suitability of gross pollution traps for large rubbish in the stormwater drainage systems.