A high-tech investigation involving EPA Victoria and the community has identified possible sources of persistent pollution in Blackburn Lake setting off a campaign of inspections of industrial sites upstream.
EPA Northern Metropolitan Regional Manager Chloe Bernett says the cooperative operation was a response to 40 pollution reports from the public since 2021.
"Blackburn Lake Sanctuary is a popular community asset, with recreational facilities and habitat for wildlife, but it has been plagued with pollution including sediment and some reports of oils, sewage, and foam," Ms Bernett said.
"EPA installed real-time water quality monitoring gear at locations around the lake, and community members made regular checks on the gear and raised awareness about reporting pollution to EPA," she said.
"While the electronics were reporting acidity levels (pH), dissolved oxygen, turbidity, temperature, algae and ammonium content, the community members could inspect the equipment and report back on aspects like the appearance of the water and any odour they encountered."
EPA's Water Sciences Unit worked with regional EPA staff to study the pattern and types of pollution, and whether the pollution was specific to particular days or times, which helped narrow down the list of likely sources.
"High turbidity suggested building sites, and spikes in acidity pointed to concrete washwaters," Ms Bernett said.
"We identified nine businesses and inspected all of them over a three-day operation. We've dispensed compliance advice to some of them, and there will be more inspections and enforcement action where necessary," she said.
"Combining data from electronic monitoring, reports from the public and observations by EPA field staff and community volunteers allowed us to track pollution back to likely sources and take action."
EPA reported back to the community on 24 February at the Clean Waterway Expo held in Blackburn Lakes Sanctuary and received positive feedback.
"EPA and the community members who have done so much to help will be watching Blackburn Lake and monitoring the results of our efforts," Ms Bernett said.
Members of the public can report pollution by calling EPA's 24-hour hotline on 1300 372 842 or providing details online at epa.vic.gov.au/report-pollution/reporting-pollution
