An investigation is underway into several complaints of a foul smell lingering in several Rockingham and Mandurah suburbs.
The Department of Water and Environmental Regulation (DWER) is currently carrying out odour surveys in Secret Harbour, Golden Bay, Singleton, Lakelands and surrounding areas after an influx of complaints from residents.
DWER are now investigating where the smell is coming from.
"Surveys across local licensed facilities (e.g. wastewater treatment plants, waste transfer stations, landfills, composting operations and piggeries), as well as several natural sources of odour including Black Swan Lake, Goegrup Lake and sections of the Serpentine River with potential to contribute to odour emissions, are being investigated," a DWER statement read.
"Initial investigations by DWER officers suggest that there are several natural sources of odour including Black Swan Lake, Goegrup Lake and sections of the Serpentine River contributing to the odours being experienced in the area.
"These natural odours are likely due to the reduced inflow of water into the lake and river system following a drier than average winter period coupled with warmer than average summer temperatures.
"This natural process results in organic matter on the lake floor and riverbanks being exposed to the air and sun, causing it to break down (oxidise) resulting in the release of often sulphurous odours, often described as ‘rotten egg smell’."
DWER encourages residents to report any odours by calling the Pollution Watch Hotline on 1300 784 782 or online.
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