Melbourne Water has contained polluted water that entered Merlynston and Campbellfield Creek, as a result of a fire in a nearby Broadmeadows tyre recycling yard.
The runoff was contained at several sites and pumped out to be treated at the Western Treatment Plant.
Melbourne Water Manager Waterways Delivery West Region, Cameron Howie, said runoff that entered Merlynston Creek, Jack Roper Reserve and Campbellfield Creek could be harmful to animals or humans.
“We have installed public warning signage at Jack Roper Reserve and a nearby wetland advising people and their pets to avoid contact with the water and make sure that it does not come into contact with their skin or eyes,” Mr Howie said.
“We will continue to sample the water regularly at several sites and conduct wildlife inspections to keep a close watch on the problem,” Mr Howie said.
Melbourne Water said they will continue to monitor the situation, especially in light of forecasted rainfall.
Melbourne Water is working with the EPA and Yarra Valley Water to manage the runoff, and working with Hume City Council to manage the recreational areas impacted by the water quality.